JP4435521B2 - Method for manufacturing magnetoresistive element - Google Patents

Description

    The present invention relates to a magnetoresistive effect element, a manufacturing method thereof, a magnetic head, and a magnetic reproducing apparatus, and more specifically, a magnetoresistive effect element having a structure in which a sense current flows in a direction perpendicular to a film surface of a magnetoresistive effect film, and The present invention relates to a manufacturing method thereof, a magnetic head using the same, and a magnetic reproducing apparatus.

  In recent years, the magnetic recording density of HDDs (Hard Disk Drives) has been dramatically improved, but further higher recording density is desired. Due to the miniaturization of the recording bit size associated with the higher recording density, the conventional thin film head has insufficient reproduction sensitivity, and the magnetoresistive head (MR head) using the magnetoresistive effect is the mainstream now. It has become. Among them, a spin-valve type giant magnetoresistive head (SVGMR head) has attracted attention as a particularly large magnetoresistive effect.

  FIG. 29 is a conceptual diagram illustrating a schematic cross-sectional structure of a spin valve film. That is, the spin valve film 100 has a configuration in which a ferromagnetic layer F, a nonmagnetic layer S, a ferromagnetic layer P, and an antiferromagnetic layer A are stacked in this order. Of the two ferromagnetic layers F and P that are in a magnetically uncoupled state with the nonmagnetic layer S interposed therebetween, one of the ferromagnetic layers P is fixed in magnetization by an exchange bias using an antiferromagnetic material A or the like. The other ferromagnetic layer F can be easily rotated by an external magnetic field (signal magnetic field or the like). Then, only the magnetization of the ferromagnetic layer F is rotated by an external magnetic field, and the relative angle between the magnetization directions of the two ferromagnetic layers P and F can be changed to obtain a large magnetoresistance effect (for example, non-patented). Reference 1).

  Here, the ferromagnetic layer F is referred to as “free layer”, “magnetic field sensitive layer” or “magnetization free layer”, and the ferromagnetic layer P is referred to as “pinned layer” or “magnetization pinned layer”. The nonmagnetic layer S is often referred to as a “spacer layer”, “magnetic coupling blocking layer”, or the like.

  Since the spin valve film can rotate the magnetization of the free layer, that is, the ferromagnetic layer F even in a low magnetic field, high sensitivity can be achieved, and it is suitable for an MR element for an MR head.

  For such a spin valve element, it is necessary to pass a “sense current” in order to detect a change in resistance due to a magnetic field.

  For this purpose, a method is generally used in which a sense current is allowed to flow parallel to the film surface and the resistance in the direction parallel to the film surface is measured. This method is generally called a “CIP (current-in-plane)” method.

  In the case of the CIP method, an MR change rate of about 10 to 20% can be obtained. Further, in a shield type MR head that is generally used at present, the spin valve element is used in a plane shape that is almost square, so that the resistance of the MR element is substantially equal to the surface electrical resistance value of the MR film. Therefore, in the CIP type spin valve film, it is possible to obtain good S / N characteristics by setting the surface electric resistance value to 5 to 30Ω. Such a resistance value can be realized relatively easily by reducing the film thickness of the entire spin valve film. Because of these advantages, at present, a CIP type spin valve film is generally used as an MR element for an MR head.

  On the other hand, as a method for obtaining a large MR exceeding 30%, a magnetoresistive effect of flowing a sense current in a direction perpendicular to the film surface (CPP) in an artificial lattice in which a magnetic material and a nonmagnetic pair are laminated. An element (hereinafter referred to as “CPP type artificial lattice”) has been proposed.

  In the CPP type artificial lattice type magnetoresistive effect element, electrodes are respectively provided above and below an artificial lattice in which ferromagnetic layers and nonmagnetic layers are alternately stacked, and a sense current flows in a direction perpendicular to the film surface. In this configuration, it is known that the probability that the sense current crosses the magnetic layer / nonmagnetic layer interface is high, so that a good interface effect can be obtained and a large MR ratio can be obtained.

  However, on the other hand, when the MR element is used for an MR head, each magnetic layer is controlled so that Barkhausen noise or the like is not generated at the same time while controlling the magnetization of the magnetic layer so that an external magnetic field can be measured efficiently. It becomes necessary to make a single magnetic domain. However, as described above, in order to obtain a resistance value in a CPP type MR element, it is necessary to alternately laminate a magnetic layer and a non-magnetic layer several times. It is technically difficult to control the magnetization.

  On the other hand, it is conceivable to adopt the CPP method in a spin valve structure using FeMn / NiFe / Cu / NiFe, FeMn / CoFe / Cu / CoFe, or the like.

  That is, a sense current is passed in a direction perpendicular to the film surface with respect to the laminated film having the spin valve structure. However, since the number of pin layers and free layers is greatly reduced as compared with the artificial lattice type, the resistance value is further reduced, and the resistance change rate is also reduced.

  In this regard, a magnetoresistive effect element in which a nonmagnetic film made of a mixture of an insulator and a conductor is inserted has been proposed (see Patent Document 1).

FIG. 1 of Patent Document 1 describes a CPP type magnetoresistive effect element in which a nonmagnetic film having a structure in which a conductor C is surrounded by an insulator I is inserted. However, as a specific example of such a nonmagnetic film, the one described in the same publication is that a nonmagnetic film is deposited to a thickness of 2 nanometers or 5 nanometers using a composite target of Al ₂ O ₃ and Cu. These examples are only examples, and it was not clear what specific non-magnetic film structure can be formed.
Phys. Rev. B., Vol. 45, 806 (1992), J. Appl. Phys. Vol. 69, 4774 (1991) Japanese Patent No. 3293437

  As described above, various structures such as a CIP type spin valve film, a CPP type artificial lattice, and a CPP type spin valve have been proposed. However, the magnetic recording density continues to increase at an annual rate of 60% or more, and further increase in output is required in the future. However, at present, it is difficult to realize a spin valve film that can be used at a high recording density exceeding 100 Gbit / inch 2 and has an appropriate resistance value, a large MR variation, and high magnetic sensitivity. It has become.

  The present invention has been made on the basis of recognition of such a problem, and an object of the present invention is to provide a practical magnetoresistive element having an appropriate resistance value while effectively using the spin-dependent scattering effect, and a method for manufacturing the same. Another object is to provide a magnetic head and a magnetic reproducing apparatus using the same.

According to the method of manufacturing a magnetoresistive element of the present invention, the first magnetization direction is substantially fixed in one direction.
A magnetoresistive film having a ferromagnetic layer, a second ferromagnetic layer whose magnetization direction changes according to an external magnetic field, and an intermediate layer formed between the first and second ferromagnetic layers; Manufacturing a magnetoresistive effect element having a pair of electrodes electrically connected to the magnetoresistive effect film that allows a sense current to flow in a direction substantially perpendicular to the film surface of the magnetoresistive effect film A phase separation method in which a layer made of an alloy containing two or more elements is separated into a first phase and a second phase in a film plane by spin-solid decomposition or formation of a GP zone in a solid phase. by cause
At least one selected from the group consisting of oxygen, nitrogen, fluorine, and carbon than the other
A high-resistance phase containing one element at a high concentration and having a relatively high resistance;
The pair of electrodes having the first and second phases which are low resistance phases having a relatively lower resistance than the first phase.
A step of forming a phase separation layer formed therebetween is provided.

  According to the above configuration, a practical magnetoresistive element having an appropriate resistance value can be reliably and easily manufactured while effectively using the spin-dependent scattering effect.

  According to the present invention, as described above, by providing the phase separation layer having a unique configuration, the sense current can be narrowed, the effective element size can be reduced, and a large resistance change can be obtained.

  On the other hand, by providing the magnetic coupling blocking layer, the magnetic coupling between the magnetization fixed layer and the magnetization free layer is reliably blocked, and further, the magnetic characteristics of the magnetic layer are improved by acting as a buffer layer. It is also possible.

  As a result, it is possible to provide a magnetoresistive effect element having a large MR variation and an appropriate resistance value. By making this magnetoresistive element a magnetic head, an HDD having a high surface recording density and a magnetic memory capable of high integration can be realized, and the industrial merit is great.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a conceptual diagram showing a cross-sectional structure of the magnetoresistive effect element according to the first embodiment of the present invention. In the figure, 1 is a substrate electrode, 2 is an underlayer, 3 is an antiferromagnetic film, 4 is a magnetization pinned layer (pinned layer), 5A is a magnetic coupling blocking layer, 5B is an interface adjustment layer, and 6 is a magnetization free layer ( Free layer), 7 is a protective layer, 8 is an upper electrode layer, and 9 is a phase separation layer. That is, this element is a CPP type magnetoresistive element in which a sense current I (in the direction of the arrow in the figure, or the direction opposite to the arrow) is passed between the substrate electrode 1 and the upper electrode layer 9.

  The magnetic coupling blocking layer 5A, the interface adjustment layer 5B, and the phase separation layer 9 serve as an intermediate layer (spacer layer) that blocks the magnetic coupling between the magnetization fixed layer 4 and the magnetization free layer 6. .

  In addition, the phase separation layer 9 has an effect of effectively reducing the element size and increasing the resistance change amount by narrowing down the current path of the sense current I. Such a current confinement effect, as conceptually illustrated in FIG. 2, causes the current to concentrate because the phase separation layer 9 has a two-dimensional “fluctuation” of resistance in the film surface. It comes from having a part.

  FIG. 2 is an explanatory diagram conceptually showing how the phase separation layer 9 constricts the sense current. That is, the phase separation layer 9 has two-dimensional fluctuations in its electric resistance value, and has a region 9A having a relatively high resistance and a region 9B having a relatively low resistance. Then, the sense current I supplied from the electrode to the spin valve film is blocked by the high-resistance region 9A and flows through the locally formed low-resistance region 9B in the phase separation layer 9. In the present embodiment, since the current flows through such a low resistance region 9B, the current characteristic regarding the phase separation layer 9 maintains “ohmic” to the last.

  In the case of a so-called TMR (tunneling magnetoresistance effect) element, an insulating layer is provided between a pair of magnetic layers, and sense current passes through the insulating layer by tunneling. Therefore, the current characteristic with respect to the insulating layer in the TMR element shows a so-called “tunnel characteristic”.

  On the other hand, in the magnetoresistive effect element according to the present embodiment, the sense current passes through the low-resistance region 9B of the phase separation layer 9 and essentially exhibits ohmic characteristics. Are very different.

  One method for investigating whether the film characteristics are TMR-like or ohmic current paths is to examine the relationship between the sense current and the magnetoresistive effect. That is, in the case of TMR, if the resistance is low, breakdown is easily caused and stability cannot be obtained. If the magnetoresistance change rate tends to decrease due to an increase in the sense current, the possibility of TMR is very high.

  It can also be distinguished by examining the temperature dependence of resistance. That is, in the ohmic system, when the temperature is lowered to about minus 200 degrees Celsius, the resistance is significantly decreased as compared to the room temperature, but the TMR is significantly increased.

  FIG. 3 is a conceptual diagram illustrating a specific example of a planar configuration of the phase separation layer 9. As shown in the figure, as the phase separation layer 9, a region 9A having a high resistance and a region 9B having a low resistance are formed in a separated state.

  Such a two-dimensional separation structure can be realized by utilizing solid phase phase separation such as “spinodal decomposition” and “GP zone (Guinier-Preston zone)”. That is, the phase separation layer 9 provided between the magnetization pinned layer 4 and the magnetization free layer 6 has an alloy composed of two or more elements converted into two or more phases by a mechanism such as spinodal decomposition or formation of a GP zone. It has a solid phase separated tissue.

  Further, in the present embodiment, any one of a plurality of such phase-separated phases is preferentially oxidized by exposure to an oxygen atmosphere, pretreatment such as oxygen radical irradiation, or heat treatment. That is, the region 9A (insulating phase) having a relatively high resistance is formed by oxidizing part of the phase separation layer that has undergone solid phase separation by a mechanism such as spinodal decomposition or formation of a GP zone. A structure in which unoxidized regions 9B (conductive phase) having relatively low resistance are distributed is formed between these regions 9A.

  Therefore, for example, when phase separation into two phases by a mechanism such as spinodal decomposition, if one phase is preferentially oxidized compared to the other phase, a conductive phase is distributed in the insulating phase. It becomes easy to form the structure. For this purpose, for example, it is desirable to select an alloy system that is phase-separated into a phase containing many elements that are easily oxidized and a phase containing many elements that are not easily oxidized.

According to “Oxide Handbook (supervised by Samsonov: published by Nihon-Soshin Kogyo 1969)”, the free energy of oxidation generation of main elements related to the present invention is as shown in Table 1.


Here, the smaller the value of the free energy for oxidation generation, the easier it is to oxidize. That is, in Table 1, the elements listed above are less likely to be oxidized, and the elements listed below are more likely to be oxidized.

  The noble metal elements such as gold (Au), silver (Ag), and copper (Cu) used as the low resistance phase in the present invention have a higher free energy for oxidation generation than other elements and are in a low resistance phase in which an oxide is not easily formed. Is suitable. In addition, iron (Fe), cobalt (Co), nickel (Ni), etc. are also easier to form oxides than noble metal elements, but lower levels, for example, tantalum (Ta), niobium (Nb), Compared to aluminum (Al), silicon (Si), etc., it is less likely to be oxidized.

  Therefore, it is effective to appropriately select an alloy-based element to be phase-separated in consideration of the magnitude relationship of the free energy of oxidation generation.

  Instead of oxidation, as will be described in detail later, nitridation, fluoride, carbonization, etc. may be used. In addition, depending on the type of material of the phase separation layer 9, even with this phase separation alone, the specific phase of the insulating phase 9 </ b> A may be separated into a phase that is 10 to 100 times larger than the specific resistance of the highly conductive phase 9 </ b> B. Even in this state, it may have a function as a phase separation layer.

  According to this embodiment, the formation of a phase separation structure corresponding to these regions 9A and 9B is facilitated by utilizing solid phase phase separation such as spinodal decomposition and GP zone formation. Moreover, the phase separation ratio and distribution can be reliably and easily controlled.

  According to the study by the inventors, the particle size of the phase-separated highly conductive phase 9B is 0.8 to 4 times the film thickness of the phase-separated layer 9, and the interval between the highly conductive phases is 1 nm or more and 10 nm. It was found that a practical CPP type magnetoresistive element having an appropriate resistance value while effectively using the spin-dependent scattering effect can be obtained when the range is less than the range. Such a particle diameter and the space | interval of a highly conductive phase can be measured by observation by TEM (transmission electron microscopy), for example.

  When phase separation mechanisms such as spinodal decomposition and GP zone formation are used, the particle size and spacing of the highly conductive phase depends on the material composition of the phase separation layer 9 and the phase separation promotion process conditions (eg, substrate temperature, rare gas such as Ar). Etc.) can be regularly controlled to a desired value within the above range by plasma irradiation, ion irradiation of rare gas such as Ar). Also, there is little dispersion or “variation”. For this reason, the proportion of the high conductive phase in the phase separation layer 9 (range of 1 to 20%) can be controlled with high accuracy so as to be within the above-described appropriate range, and has a stable characteristic. The effect element can be manufactured.

On the other hand, in the phase separation layer composed of the Al ₂ O ₃ insulating portion and the Cu conductive portion studied as a comparative example, the interval between the conductive portions is determined by the grain size of the magnetization pinned layer and the magnetization free layer below it, and thus becomes 10 nm or more. Easily sparse conductive parts. As a result, when the recording density is improved and the element size is reduced, the number of conductive portions is also reduced. Therefore, it becomes difficult to control the proportion of the high conductive layer in the phase separation layer, and the element resistance and the resistance change amount are controlled. Will become difficult.

  FIG. 4 is a flowchart showing a part of the process of forming phase separation layer 9 in the embodiment of the present invention.

  FIG. 5 is a conceptual diagram illustrating the change in the planar structure of the phase separation layer 9.

  In forming the phase separation layer 9, first, the base material M is formed in Step S1. The base material M can be deposited in a thin film by a method such as sputtering.

  In a state where the base material M is not yet spinodal decomposed or a GP zone is not formed immediately after deposition or immediately after deposition, as shown in FIG. 5A, the structure is almost uniform.

  In the present embodiment, the phase decomposition process S2 can be performed simultaneously with or after the thin film deposition process. For example, annealing at a high temperature for a long time, irradiation with an ion beam, and the like.

  When a phase decomposition process such as annealing or ion beam irradiation is performed as step S2, as shown in FIG. 5B, concentration modulation occurs in the base material M, and decomposition into phases D1 and D2 occurs. To do. In general, in the case of spinodal decomposition, nucleation is not required, and compositional fluctuations continuously increase. Therefore, it is considered that decomposition does not show an incubation period and maintains complete consistency with the parent phase. ing. Further, in the case of aluminum (Al) -4% copper (Cu) alloy or the like, a phase having a high copper composition is formed by aging treatment at room temperature or at elevated temperature, resulting in phase separation. For example, when so-called “two-stage aging” in which precipitation aging is performed at a high temperature after aging treatment at room temperature, a phase separation structure in which fine regions having a high copper composition are uniformly dispersed is obtained.

  As described above, by performing the decomposition process, “fluctuation” of the composition occurs in the base material M, and as a result, a phase separation structure as illustrated in FIG. 5B is formed.

  Next, an oxidation process is performed as step S3. Examples of the oxidation process S3 include a method of exposing to an atmosphere in which oxygen is introduced into a film forming chamber, a method of irradiating oxygen radicals, and the like. Depending on the material used, processes such as nitriding, fluorination, and carbonizing may be performed instead of oxidation.

  When such an oxidation process is performed, a phase having a composition that is easily oxidized is preferentially oxidized among the separated phases D1 and D2. For example, in the example shown in FIG. 5C, the phase D1 is oxidized to form a region 9A having a high resistance. On the other hand, the phase D2 in which the oxidation has not progressed so much constitutes a region 9B having a low resistance.

  FIG. 6 is a flowchart showing another method for forming the phase separation layer 9.

  That is, the phase decomposition process and the oxidation process are not necessarily performed separately, and may be performed simultaneously.

  For example, these processes S2 and S3 can be performed simultaneously by exposing to an oxygen atmosphere or irradiating oxygen radicals simultaneously with annealing for phase separation.

  Still further, such decomposition and oxidation processes can be performed simultaneously with the deposition process of the base material M. For example, the deposition process and the phase decomposition and oxidation processes can be simultaneously performed by irradiating the substrate with an ion beam containing oxygen ions simultaneously with the formation of the base material M.

  As described above, when the decomposition process S2 and the oxidation process S3 are performed simultaneously, the base material M may be oxidized and remain, and may constitute a part of the region 9A having a high resistance.

  FIG. 7 is a conceptual cross-sectional view showing an example in which two or more types of solid phase separation are performed depending on the types of constituent elements forming the base material. In this specific example, since the base material of the phase separation layer 9 is composed of two or more kinds of elements that undergo phase separation in the solid phase, the phase separation layer 9 undergoes two types of spinodal decomposition, and phase D1 and phase D2 The regions 9A (D1) and 9A (D2) having high resistance due to oxidation are formed, and the conductive phase 9B having low resistance is constituted by a metal element different from the regions 9A (D1) and 9A (D2) having high resistance. . Even in such a structure of three or more phases composed of two or more types of high-resistance phases and low-resistance phases, it can be used as the phase separation layer 9 of the present embodiment.

  On the other hand, in the present embodiment, an ion beam irradiation method as shown in FIG. 8 is also effective as the decomposition process S2 that causes spinodal decomposition and GP zone formation. That is, the energy for causing the composition fluctuation in the base material M formed in a thin film and causing phase separation can be given by ion beam irradiation.

  As an ion beam used in this case, for example, a rare gas element such as argon (Ar), xenon (Xe), or krypton (Kr) can be used. In addition, oxygen (or nitrogen, fluorine, carbon) can be used in the case of performing simultaneously with the oxidation (or nitridation, fluoride, carbonization) process.

  On the other hand, the irradiation conditions can be appropriately selected within a range in which etching of the base material M of the phase separation layer 9 does not occur remarkably. Specifically, for example, an argon ion beam can be irradiated at an acceleration voltage of 50 volts (V) and an input power of about 50 watts (W).

  Next, a specific example of the base material M of the phase separation layer according to this embodiment will be described.

  As one of the specific base materials M of the phase separation layer 9 having such a solid phase separation structure, silver (Ag), gold (Au), copper (Cu), platinum (Pt), palladium (Pd) ), Iridium (Ir), osmium (Os) and copper (Cu), one or more kinds of noble metal-nickel (Ni) -iron (Fe) -cobalt (Co) alloys selected from the group consisting of .

  Then, the noble metal-Ni-Fe alloy and the noble metal-Ni-Co alloy phase separation layer thus formed are subjected to an oxidation treatment using oxygen radicals or the like as described above to thereby provide Ni-Fe and Ni-Co. The rich phase (D1) is selectively oxidized to become a highly insulating phase (region 9A). Furthermore, the phase separation between the conductive phase (noble metal) and the insulating phase (Ni—Fe—Ox and Ni—Co—Ox) of the phase separation layer 9 proceeds by the heat treatment after forming the laminated structure of the magnetoresistive film, The purity of the noble metal that is the conductive phase is increased, and the resistance is further lowered.

Such phase separation and selective oxidation are performed when the composition formula is Q _x (Ni _100-y (Fe _100-z Co _z ) _y ) _100-x , where x is a noble metal element, and x is 1% or more. Noble metal-nickel (Ni) -iron (Fe) -cobalt represented by 50% or less, y being 50% or less and 0% or more, 0% ≦ z ≦ 100%, z being 0% or more and 100% or less It is obtained in the above composition range of the (Co) alloy. Alternatively, in the chemical formula consisting of Q _x (Co _100-y (Fe _100-z Ni _z ) _y ) _100-x , the composition x is 1 atom% or more and 50 atom% or less, and the composition y is 0 atom% or more and 50 atoms % Or less, and the composition z is in the range of 0 atomic% or more and 100 atomic% or less.

  Here, the “noble metal element” is at least one of silver (Ag), gold (Au), platinum (Pt), palladium (Pd), iridium (Ir), osmium (Os), and copper (Cu). It is desirable to use In that case, it is not limited to any one of these noble metals, and two or more kinds of elements may be combined. In this case, the composition x refers to the total composition of those selected as the noble metal elements. For example, when silver and platinum are selected as the noble metal element Q, the composition x is the sum of the silver composition and the platinum composition.

  In the present application, the term “total composition” refers to the sum of the compositions of the respective elements selected from a predetermined selection range.

As another mother material of the phase separation layer 9, is represented by a compositional formula of _{(Al 100-y Q y)} 100-x M x, silver as the element M (Ag), gold (Au), platinum (Pt ), Copper (Cu), palladium (Pd), iridium (Ir), and osmium (Os), the composition x is 1% or more and 40% or less, and the element Q Magnesium (Mg), calcium (Ca), silicon (Si), germanium (Ge), boron (B), tantalum (Ta), tungsten (W), niobium (Nb), zirconium (Zr), titanium (Ti), It is composed of one or more selected from the group consisting of chromium (Cr), zinc (Zn), lithium (Li), and gallium (Ga), and the composition y is in the range of more than 0 atomic% and not more than 30 atomic%. The aluminum (Al) alloy represented by these can be mentioned.

  In this alloy, phase separation occurs between a phase having a high aluminum composition and a phase having a low aluminum composition. Therefore, by performing the oxidation treatment, a phase with high electrical resistance (region 9A) in which aluminum and element Q are oxidized and a metal (M) phase (region 9B) with relatively high purity and low electrical resistance can be obtained. Is possible. Furthermore, by setting the range of the composition x to 1% or more and 40% or less and using a thin film forming method for sputtering or the like, spinodal decomposition and nucleation are promoted at a low temperature. The composition x is more preferably in the range of 5% to 20%. If the composition x is within this range, the phase with high electrical resistance (region 9A) is interspersed with the phase with low electrical resistance (region 9B), which effectively restricts the path of the sense current and is good. This is because a current confinement effect can be obtained.

FIG. 9A is a schematic diagram of a cross-sectional TEM image of a phase separation layer formed by phase separation using an Al ₉₀ Ag ₁₀ alloy as a base material and oxidation treatment. FIG. 4B is a schematic diagram showing a profile of elemental analysis of the phase separation layer by nano EDX (Energy Dispersive X-ray photoelectron spectroscopy).

  A region having a high composition of aluminum (Al) is oxidized to form a phase D1 having a high electrical resistance, and a region having a high composition of silver (Ag) forms a phase D2 having a low resistance.

On the other hand, as another mother material of the phase separation layer 9, is represented by a compositional formula of _{(Mg 100-y Q y)} 100-x M x, silver as the element M (Ag), gold (Au), platinum ( Pt), palladium (Pd), copper (Cu), iridium (Ir), and osmium (Os), at least one selected from the group consisting of, composition x is 1% to 40 atomic%, The element Q is composed of at least one selected from the group consisting of calcium (Ca), silicon (Si), germanium (Ge), zinc (Zn), lithium (Li), and gallium (Ga), and the composition y is 0. A magnesium (Mg) alloy represented by a range of not less than 30% and not more than 30% can be given.

  In this alloy, phase separation occurs between a phase having a high magnesium composition and a phase having a low magnesium composition. Therefore, by performing the oxidation treatment, it is possible to obtain a phase with high electrical resistance (region 9A) in which magnesium and element Q are oxidized and a metal (M) phase (region 9B) with relatively high purity and low electrical resistance. Is possible. Furthermore, by setting the range of the composition x to 1% or more and 40% or less and using a thin film forming method for sputtering or the like, spinodal decomposition and nucleation are promoted at a low temperature. The composition x is more preferably in the range of 5% to 20%. If the composition x is within this range, the phase with high electrical resistance (region 9A) is interspersed with the phase with low electrical resistance (region 9B), which effectively restricts the path of the sense current and is good. This is because a current confinement effect can be obtained.

Alternatively, as another base material of the phase separation layer 9, the composition formula is represented by (Si _100-y Q _y ) _100-x M _x , and the element M is silver (Ag), gold (Au), platinum (Pt ), Copper (Cu), palladium (Pd), iridium (Ir), and osmium (Os), and the composition x is 1 atomic% or more and 40 atomic% or less, and the element Q is composed of one or more selected from the group consisting of magnesium (Mg), calcium (Ca), magnesium (Mg), germanium (Ge), zinc (Zn), lithium (Li), and gallium (Ga). And a silicon (Si) alloy whose composition y is in the range of 0 atomic% to 30 atomic%.

  In this alloy, phase separation occurs between a phase having a high silicon composition and a phase having a low silicon composition. Therefore, by performing the oxidation treatment, a phase having high electrical resistance (region 9A) in which silicon and element X are oxidized and a metal (M) phase (region 9B) having relatively high purity and low electrical resistance can be obtained. Is possible. Furthermore, by setting the range of the composition x to 1% or more and 40% or less and using a thin film forming method for sputtering or the like, spinodal decomposition and nucleation are promoted at a low temperature. The composition x is more preferably in the range of 5% to 20%. If the composition x is within this range, the phase with high electrical resistance (region 9A) is interspersed with the phase with low electrical resistance (region 9B), which effectively restricts the path of the sense current and is good. This is because a current confinement effect can be obtained.

Alternatively, as another base material of the phase separation layer 9, the composition formula is represented by (Mn _100-y Q _y ) _100-x M _x , and the element M is silver (Ag), gold (Au), platinum (Pt ), Copper (Cu), palladium (Pd), iridium (Ir), and osmium (Os), and the composition x is 1 atomic% or more and 40 atomic% or less, and the element Q is any one selected from the group consisting of magnesium (Mg), calcium (Ca), magnesium (Mg), germanium (Ge), zinc (Zn), lithium (Li), gallium (Ga), and silicon (Si). Mention may be made of a manganese (Mn) alloy composed of one or more elements and having a composition y in the range of 0 atomic% to 30 atomic%.

  In this alloy, phase separation occurs between a phase having a high manganese composition and a phase having a low manganese composition. Therefore, by performing the oxidation treatment, a phase with high electrical resistance (region 9A) in which manganese and element X are oxidized and a metal (M) phase (region 9B) with relatively high purity and low electrical resistance can be obtained. Is possible. Furthermore, by setting the range of the composition x to 1% or more and 40% or less and using a thin film forming method for sputtering or the like, spinodal decomposition and nucleation are promoted at a low temperature. This x is more preferably in the range of 5% to 20%. If the composition x is within this range, the phase with high electrical resistance (region 9A) is interspersed with the phase with low electrical resistance (region 9B), which effectively restricts the path of the sense current and is good. This is because a current confinement effect can be obtained.

Further, as other base materials of the phase separation layer 9, a low resistance phase having magnetism mainly composed of iron (Fe) and molybdenum (Mo), magnesium (Mg), calcium (Ca), titanium (Ti), At least one element selected from the second group consisting of zirconium (Zr), niobium (Nb), hafnium (Hf), tantalum (Ta), boron (B), aluminum (Al), and silicon (Si). an alloy including, in the case where the element selected from the second group represented by the formula M _100-x Fe _x as M, the composition x of iron in the range of 50 atomic% at 1 atomic% or more An alloy can be mentioned.

  In this alloy, phase separation occurs between a phase having a high iron composition and a phase having a low iron composition. Therefore, by performing oxidation treatment, it is possible to obtain a phase with high electrical resistance (region 9A) in which the element M is mainly oxidized and an iron phase (region 9B) with relatively high purity and low electrical resistance. . This is because, as described above with reference to Table 1, all of the elements constituting the second group have lower free energy for oxide formation than iron (Fe) and are more easily oxidized than iron (Fe). is there.

  Furthermore, by setting the range of the composition x to 1% or more and 40% or less and using a thin film forming method for sputtering or the like, spinodal decomposition and nucleation are promoted at a low temperature. This x is more preferably in the range of 5% to 20%. If the composition x is within this range, the phase with high electrical resistance (region 9A) is interspersed with the phase with low electrical resistance (region 9B), which effectively restricts the path of the sense current and is good. This is because a current confinement effect can be obtained.

In addition, other base materials of the phase separation layer 9 include a low resistance phase having magnetism mainly composed of nickel (Ni), molybdenum (Mo), magnesium (Mg), tungsten (W), titanium (Ti), At least one element selected from the second group consisting of zirconium (Zr), niobium (Nb), hafnium (Hf), tantalum (Ta), boron (B), aluminum (Al), and silicon (Si). an alloy including, in the case where an element selected from the second group represented by the formula M _100-x Ni _x as M, the composition x of nickel in the range of 50 atomic% at 1 atomic% or more An alloy can be mentioned.

  In this alloy, phase separation occurs between a phase having a high nickel composition and a phase having a low iron composition. Therefore, by performing the oxidation treatment, it is possible to obtain a phase with high electrical resistance (region 9A) in which the element M is mainly oxidized and a nickel phase (region 9B) with relatively high purity and low electrical resistance. . This is because, as described above with reference to Table 1, all of these elements constituting the second group have lower oxide formation free energy than nickel (Ni) and are more easily oxidized than nickel (Ni). is there.

  Furthermore, by setting the range of the composition x to 1% or more and 40% or less and using a thin film forming method for sputtering or the like, spinodal decomposition and nucleation are promoted at a low temperature. This x is more preferably in the range of 5% to 20%. If the composition x is within this range, the phase with high electrical resistance (region 9A) is interspersed with the phase with low electrical resistance (region 9B), which effectively restricts the path of the sense current and is good. This is because a current confinement effect can be obtained.

Further, as another base material of the phase separation layer 9, a low-resistance phase having magnetism mainly composed of cobalt (Co) and molybdenum (Mo), magnesium (Mg), tungsten (W), titanium (Ti), At least selected from the second group consisting of zirconium (Zr), niobium (Nb), hafnium (Hf), tantalum (Ta), boron (B), aluminum (Al), chromium (Cr) and vanadium (V). An alloy containing one element, where the element selected from the second group is represented by M and represented by the composition formula M _100-x Co _x , the cobalt composition x is 1 atom% or more and 50 atoms An alloy having a range of% or less can be given.

  In this alloy, phase separation occurs between a phase having a high cobalt composition and a phase having a low iron composition. Therefore, by performing the oxidation treatment, it is possible to obtain a phase with high electrical resistance (region 9A) in which the element M is mainly oxidized and a cobalt phase (region 9B) with relatively high purity and low electrical resistance. . This is because, as described above with reference to Table 1, all of the elements constituting the second group have lower free energy for oxide formation than cobalt (Co) and are more easily oxidized than cobalt (Co). is there.

  Furthermore, by setting the range of the composition x to 1% or more and 40% or less and using a thin film forming method for sputtering or the like, spinodal decomposition and nucleation are promoted at a low temperature. This x is more preferably in the range of 5% to 20%. If the composition x is within this range, the phase with high electrical resistance (region 9A) is interspersed with the phase with low electrical resistance (region 9B), which effectively restricts the path of the sense current and is good. This is because a current confinement effect can be obtained.

  In order to form a GP zone, an aluminum (Al) -copper (Cu) alloy, an aluminum (Al) -silver (Ag) alloy, an aluminum (Al) -zinc (Zn) -magnesium (Mg) alloy An alloy or the like can be used.

  In addition, in the base material alloy of the phase separation layer 9 described above, chromium (Cr), titanium (Ti), zirconium (as additives) are used for controlling oxygen absorption, spinodal decomposition, and particle size control of the precipitated phase. Elements such as Zr), hafnium (Hf), molybdenum (Mo), tin (Sn), lithium (Li), and zinc (Zn) may be added in an amount of several atomic percent.

  On the other hand, as another base material of the phase separation layer 9, a material containing two or more kinds of base materials by solid phase phase separation such as spinodal decomposition as mentioned above, and a solid phase inside spinodal decomposition or the like You may laminate | stack the base material by isolation | separation, and the alloy which does not accompany solid-phase isolation | separation. As described above, the insulating phase and the conductive phase can be uniformly formed at a predetermined ratio by solid phase phase separation such as spinodal decomposition, and an insulating phase made of a metal element different from the insulating phase is formed. Thus, it is possible to improve the withstand voltage of the phase separation layer 9.

  In addition, by laminating two or more different base materials, the generation of pinholes is greatly reduced, and a base material with internal phase separation such as spinodal decomposition and an alloy without internal phase separation. By laminating, the conductive phase of the phase separation layer of the alloy without phase separation in the solid phase is preferentially formed with the conductive phase formed by spinodal decomposition or the like as the nucleus, and as a result, when the sense current is passed The isolation voltage of the phase separation layer is greatly improved, and the reliability as a magnetoresistive effect element is greatly improved.

  FIG. 10 is a schematic view illustrating the cross-sectional structure of the phase separation layer 9 having a laminated structure. That is, the phase separation layer 9 of this specific example has a structure in which a first phase separation layer 9 ′ and a second phase separation layer 9 ″ are laminated. The first phase separation layer 9 ′ has a high resistance. The region 9A ′ has a low resistance region 9B ′. The second phase separation layer 9 ″ also has a high resistance region 9A ″ and a low resistance region 9B ″.

  The average size of the region 9B ′ is larger than that of the region 9B ″, and these regions are formed so as to substantially overlap each other when viewed in the thickness direction of the film. It can be formed by appropriately shifting the composition of the base material of 9 ′ and the phase separation layer 9 ″ or changing the kind of the base material. That is, the size of each phase after phase decomposition can be changed by shifting the composition of the base material of the upper and lower layers or changing the kind of the base material.

  For example, chromium (Cr), tantalum (Ta), niobium (Nb), boron (B), germanium, which are easily crystalline, are formed on the phase separation layer 9 ″ made of a material having excellent spinodal decomposability as described above. (Ge), tungsten (W), molybdenum (Mo), zirconium (Zr), titanium (Ti), vanadium (V), cobalt (Co), iron (Fe), nickel (Ni), silicon (Si), etc. By laminating the phase separation layer 9 ′ mainly composed of elemental oxides (which may be nitrides, borides, and carbides), in addition to forming a highly conductive phase with good controllability by spinodal decomposition, The crystallinity of the magnetic layer formed thereon can be controlled, and the soft magnetic characteristics can be improved.

  Alternatively, a phase separation layer made of a material having excellent spinodal decomposability including a magnetic oxide (such as nitride, boride, or carbide) such as cobalt (Co), iron (Fe), or nickel (Ni), and nonmagnetic The non-magnetic phase separation layer acts as a magnetic coupling blocking layer, and the magnetic coupling between the magnetic layers is suppressed by stacking the phase separation layer or the oxide layer (which may be nitride, boride or carbide). And high-conductivity phase formation with good controllability by spinodal decomposition is possible at the same time.

  Further, when the decomposition process is performed in such a laminated structure, when spinodal decomposition occurs in one of the upper and lower layers, the phase formed by decomposition (D1, D2) becomes the “trigger of spinodal decomposition in the other layer. May be.

  As a result, the positions of the regions 9A ′ and 9A ″ formed in the upper and lower layers 9 ′ and 9 ″ can be formed so as to be substantially overlapped when viewed in the thickness direction.

  In addition, although the phase-separation layer of 2 layer structure was illustrated in FIG. 10, this invention is not limited to this, A phase-separation layer may laminate | stack three or more layers. Further, the boundary between the layers is not always clear, and the structure may be such that the composition is continuously modulated along the film thickness direction of the phase separation layer.

  Further, the base material of these phase separation layers 9 is used for the purpose of improving magnetic characteristics, adjusting electric resistance, and improving crystallinity, and includes either one or both of the magnetization free layer 6 and the magnetization pinned layer 4 other than the intermediate layer. It may be inserted between one or both of the substrate electrode 1 and the upper electrode 8. For example, a configuration such as a magnetization pinned layer 4 / phase separation layer 9 / magnetization pinned layer 4 'and a magnetization pinned layer 4 / phase separation layer 9 / magnetization pinned layer 4' can be exemplified.

  On the other hand, in the phase separation layer 9, in order to increase the resistance of one phase separated and form a region 9A having a relatively high resistance, a nitridation, fluorination or carbonization process is used instead of oxidation. It is also possible to use it. That is, when the resistivity can be increased by reacting one phase separated with nitrogen (N), fluorine (F) or carbon (C), a nitriding, fluoriding or carbonizing process is performed. Can be used.

(Second Embodiment)
Next, as a second embodiment of the present invention, a phase separation layer 9 is provided in any one of the pinned layer, the magnetization free layer, the intermediate layer, and between the electrode and the ferromagnetic film, and is in contact with the phase separation layer. A magnetoresistive effect element including a magnetic coupling blocking layer will be described.

  In the magnetoresistive effect element of this embodiment, as illustrated in FIG. 1, a magnetic coupling blocking layer 5 </ b> A can be provided on at least one of the phase separation layers 9. The magnetic coupling blocking layer 5 </ b> A has a role of reliably blocking the magnetic coupling between the magnetization fixed layer 4 and the magnetization free layer 6. That is, if the magnetic coupling between the magnetization pinned layer 4 and the magnetization free layer 6 cannot be sufficiently blocked by the phase separation layer 9 alone, the magnetic coupling blocking layer 5A is provided so that these magnetic couplings can be reduced. It can be reliably shut off.

Such a magnetic coupling blocking layer 5A is represented by Q _x (Ni _100-y (Fe _100-z Co _z ) _y ) _100-x, where Q is a noble metal element as a base material of the phase separation layer 9. This is particularly effective when an alloy is used. That is, when the region 9A is formed by phase-separating this alloy, for example, some magnetism may remain in the region 9A where oxidation is insufficient. In such a case, the magnetic coupling blocking layer 5A is particularly effective for blocking the magnetic coupling between the adjacent magnetization free layer 6 and the magnetization pinned layer 4.

  Examples of the material of the magnetic coupling blocking layer 5A include copper (Cu), gold (Au), silver (Ag), rhenium (Re), osmium (Os), ruthenium (Ru), iridium (Ir), and palladium (Pd). ), Chromium (Cr), magnesium (Mg), aluminum (Al), rhodium (Rh), platinum (Pt), or the like.

  The thickness of the magnetic coupling blocking layer 5A is desirably thick enough to sufficiently block the magnetic coupling between the magnetization pinned layer 4 and the magnetization free layer 6 via the phase separation layer 9. That is, since the magnetism may remain in the phase separation layer 9 as described above, one of the magnetic coupling blocking layers 5 provided above and below it is provided with a film thickness that can reliably block the magnetic coupling. It is necessary.

  From this viewpoint, if the thickness of the magnetic coupling blocking layer 5A is 0.5 nm or less, the magnetic coupling cannot be blocked and the magnetization direction of the magnetization free layer 6 or the magnetization pinned layer 4 is disturbed. .5 nm or more is desirable.

  However, when the thickness of the magnetic coupling blocking layer 5A is increased, the current confined in the phase separation layer 9 spreads in the magnetic coupling blocking layer 5A, so that the current confinement effect is reduced. From this point of view, the thickness of the magnetic coupling blocking layer 5A is desirably 5 nm or less.

  Further, as a suitable range in which both magnetic coupling interruption and current spreading suppression are compatible, the thickness of the magnetic coupling interruption layer 5A is more preferably 1 nm or more and 3 nm or less. Magnetic coupling blocking layers may be provided above and below the phase separation layer.

  Further, the magnetic coupling blocking layer 5A may be provided above the phase separation layer, and the interface adjustment layer 5B may be provided below the phase separation layer. The interface adjustment layer 5B serves as a buffer layer for controlling the particle size and film quality of the phase separation layer 9 and the magnetization free layer 6 thereon. The interface adjustment layer 5B desirably has a small film thickness in consideration of current spreading. For this reason, the film thickness of the interface adjustment layer 5B is desirably less than 1 nm, and more desirably 0.25 nm or less.

  At this time, the interface adjusting phase separation layer 5B layer does not necessarily need to be a continuous film as viewed in the film plane, and may be partially missing. That is, a discontinuous thin film may be used as long as it has a buffer effect on the magnetization free layer 6.

  On the other hand, as another laminated structure, a magnetoresistive effect element having a so-called “dual spin valve structure” in which magnetization fixed layers are respectively provided above and below the magnetization free layer is the same as described above.

  In addition, as a material of the magnetization free layer 6 of the magnetoresistive effect element of this embodiment, the metal magnetic body which has nickel (Ni), iron (Fe), and cobalt (Co) as a main component can be mainly used. When used in magnetic sensors, they need to have good soft magnetic properties in order to increase sensitivity and reduce Barkhausen noise. From this point of view, it is desirable that the magnetization free layer 6 is laminated in the crystal axis [111] direction which is the closest packed surface of the face-centered cubic lattice. However, it may be partially a body-centered cubic lattice, or may include a hexagonal close-packed lattice or other crystal structures.

  Further, as the magnetization pinned layer 4 of the magnetoresistive effect element according to the present embodiment, a so-called “synthetic antireflection” in which two or more magnetic bodies are antiferromagnetically coupled via a nonmagnetic body such as ruthenium (Ru). A “ferromagnetic structure” may be used.

(Third embodiment)
Next, a magnetoresistive effect element in which a phase separation layer is provided between a magnetization free layer and an electrode will be described as a third embodiment of the present invention.

  FIG. 11 is a schematic view illustrating the cross-sectional structure of the magnetoresistive effect element according to this embodiment. In the figure, the same elements as those described above with reference to FIGS. 1 to 10 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this specific example, a nonmagnetic metal layer 10 is provided between the magnetization fixed layer 4 and the magnetization free layer 6. This nonmagnetic metal layer has a role of blocking the magnetic coupling between the magnetization fixed layer 4 and the magnetization free layer 6.

  A phase separation layer 9 is provided between the magnetization free layer 6 and the upper electrode 8. As the phase separation layer 9, the same one as described above with reference to the first embodiment can be used. That is, the phase separation layer 9 is used in which a current confinement effect is obtained by a phase separation structure formed by utilizing a mechanism such as spinodal decomposition or GP zone formation.

  As described above, when the phase separation layer 9 is provided between the magnetization free layer 6 and the electrode 8 adjacent thereto, the current from the electrode to the magnetization free layer 6 is converged, the element resistance is appropriately increased, and a large magnetic field is generated. Resistance change can be obtained.

  In the present invention, the first to third embodiments may be appropriately combined. That is, as described above with respect to the first embodiment, the phase separation layer 9 is provided between the magnetization pinned layer 4 and the magnetization free layer 6, and as described with respect to the second embodiment, the magnetic coupling blocking layer 5 A is provided. Further, as described with respect to the third embodiment, the phase separation layer 9 may also be provided between the magnetization free layer and the adjacent electrode.

  In this way, it is possible to synergize the current confinement effects and obtain higher element resistance and magnetoresistance change.

(Fourth embodiment)
Next, as a fourth embodiment of the present invention, a BMR (ballistic magnetoresistance effect) type resistance effect element in which a magnetization fixed layer and a magnetization free layer are connected by a minute magnetic region will be described.

  FIG. 12 is a schematic diagram showing a cross-sectional structure of a main part of the magnetoresistive effect element according to this embodiment. That is, the magnetoresistive effect element according to this embodiment has a structure in which a first magnetic layer 4, a phase separation phase 9, a second magnetic layer 6, and an upper electrode 8 are laminated on a substrate (electrode) 1 in this order. Have One of the first and second magnetic layers 4 and 6 functions as a magnetization fixed layer, and the other functions as a magnetization free layer.

  And the phase-separation layer 9 has the nonmagnetic area | region 9C and the magnetic area | region 9D provided scattered in it. The nonmagnetic region 9C is made of a material that does not substantially have magnetism. The magnetic region 9D is made of a magnetic material. These nonmagnetic region 9C and magnetic region 9D are formed as a result of phase separation of the base material by spinodal decomposition or other various phase separation mechanisms as described above with reference to the first to third embodiments. Yes. Typically, an alloy system of a magnetic element such as iron (Fe), cobalt (Co), nickel (Ni) and a nonmagnetic element can be used.

  Thus, the structure in which the first and second magnetic layers 4 and 6 are connected by the magnetic region 9D is called “magnetic microcontact” or “magnetic point contact”, and has a large magnetoresistance due to BMR (ballistic magnetoresistance). An effect is obtained.

  For example, as a magnetic resistance effect of 100% or more, a “magnetic microcontact” in which two acicular nickel (Ni) are attached together or a magnetic microcontact in which two magnetites are in contact with each other is described in the document N. Garcia, M. Munoz, and Y.-W.Zhao, Physical Review Letters, vol.82, p2923 (1999) and JJ Versluijs, MA Bari and JMD Coey, Physical Review Letters, vol.87, p26601 -1 (2001 ). Although these show a large rate of change in magnetoresistance, the method for producing the magnetic microcontacts is that two ferromagnetic materials processed into a needle shape or a triangle shape are squared together.

  On the other hand, according to this embodiment, by utilizing a mechanism such as spinodal decomposition, phase separation is caused, and a structure in which minute magnetic regions 9D are scattered in the nonmagnetic region 9C is easily formed. can do. The minute magnetic region 9D acts as a “magnetic minute contact” or “magnetic point contact” between the first and second magnetic layers 4 and 6 to obtain a large magnetoresistance effect by BMR. Is possible.

As a base material of the phase separation layer 9, a magnetic low resistance phase mainly composed of iron (Fe), molybdenum (Mo), magnesium (Mg), calcium (Ca), titanium (Ti), zirconium (Zr) , Niobium (Nb), hafnium (Hf), tantalum (Ta), boron (B), aluminum (Al), and at least one element selected from the second group consisting of silicon (Si). An alloy having an iron composition x in the range of 1 atomic% to 50 atomic% when the element selected from the second group is represented by M and represented by the composition formula M _100-x Fe _x is given. be able to.

  In this alloy, phase separation occurs between a phase having a high iron composition and a phase having a low iron composition. It is possible to form the nonmagnetic region 9C and the magnetic region 9D. By performing the oxidation treatment, it is possible to obtain the nonmagnetic region 9C in which the element M is mainly oxidized and the magnetic region D having a high iron (Fe) content.

  Also in this case, the range of the composition x is 1% or more and 40% or less, and spinodal decomposition and nucleation are promoted at a low temperature by using a thin film forming method for sputtering or the like. This x is more preferably in the range of 5% to 20%.

In addition, other base materials of the phase separation layer 9 include a low resistance phase having magnetism mainly composed of nickel (Ni), molybdenum (Mo), magnesium (Mg), tungsten (W), titanium (Ti), At least one element selected from the second group consisting of zirconium (Zr), niobium (Nb), hafnium (Hf), tantalum (Ta), boron (B), aluminum (Al), and silicon (Si). an alloy including, in the case where an element selected from the second group represented by the formula M _100-x Ni _x as M, the composition x of nickel in the range of 50 atomic% at 1 atomic% or more An alloy can be mentioned.

Further, as another base material of the phase separation layer 9, a low-resistance phase having magnetism mainly composed of cobalt (Co) and molybdenum (Mo), magnesium (Mg), tungsten (W), titanium (Ti), At least selected from the second group consisting of zirconium (Zr), niobium (Nb), hafnium (Hf), tantalum (Ta), boron (B), aluminum (Al), chromium (Cr) and vanadium (V). An alloy containing one element, where the element selected from the second group is represented by M and represented by the composition formula M _100-x Co _x , the cobalt composition x is 1 atom% or more and 50 atoms An alloy having a range of% or less can be given.

  The first to third embodiments of the present invention have been described above.

  Hereinafter, the magnetoresistive element of the present invention will be described in more detail with reference to examples.

(First embodiment)
First, as a first embodiment of the present invention, a magnetoresistive effect element formed by utilizing aluminum (Al) -silver (Ag) spinodal decomposition will be described.

In this example, the magnetoresistive effect element shown in FIG. 1 was manufactured. Then, an oxidation treatment was performed on the AlAg alloy as the phase separation layer 9. The film thickness and material of each layer constituting the magnetoresistive effect element are as follows. In addition, the code | symbol represented in FIG. 1 was attached | subjected in parenthesis to each corresponding layer.

Si substrate (1) / 5 nm Ta (2) / 200 nm Cu (2) / 10 nm PtMn (3) / 3 nm CoFe (4) /0.2 nm Cu (5A) /0.8 nm AlAg alloy (9) /0.2 nm Cu (5B) / 3 nm CoFe ( 6) / 2nmTa (7) / 200nmCu (8)

The Si substrate (1) used in the examples of the present invention is a substrate on which about 2 nanometers of SiO2 are formed on the surface by thermal oxidation treatment. The AlAg alloy had a composition x = 0, 5, 10, 20, and 40 atomic% in the composition formula Al _100-x Ag _x .

The film formation is performed using a DC magnetron sputtering method and exhausted until the ultimate vacuum becomes 10 ⁻⁵ Pa (pascal) or less. The film formation rate of each film is 0.02 to 0.1 [nm / second]. went. The upper electrode 8 has a substantially circular shape with a diameter of 1 μm. The oxidation treatment was performed by irradiating oxygen radicals after the phase separation layer 9 was formed. The heat treatment was performed at 270 ° C. for 10 hours in a state where a magnetic field of 5 kOe (Oersted) was applied.

  On the other hand, as a comparative example, a material using 3 nm Cu instead of the 0.8 nm AlAg alloy was prepared as the material of the phase separation layer 9.

When the magnetoresistive effect MR and the sheet resistance RA were measured for the magnetoresistive effect element of the present example using Al ₉₀ Ag ₁₀ (x = 10) and the comparative example, the following results were obtained.

Material of phase separation layer 9 MR RA
Cu 0.5% 0.08Ωμm ²
Al ₉₀ Ag ₁₀ (with oxidation treatment) 6.0% 0.25Ωμm ²

For al ₉₀ Ag ₁₀ alloy phase oxidation presence of the separating layer 9 using as a base material specimen, sectional TEM: its crystallinity were examined respectively (tansmission electron microscopy transmission electron microscope) observation.

  FIGS. 9A and 9B are a schematic diagram of a cross-sectional TEM image and a diagram of an elemental analysis profile using nano-EDX for a sample with oxidation treatment, as described above.

  In the case of no oxidation treatment, it was confirmed that the phase separation between Al and a width of about 1.5 nmAg due to spinodal decomposition was unclear. On the other hand, in the case of the oxidation treatment, as can be seen from FIG. 9, the phase separation of about 9 nm Al width and about 1.5 nm Ag width accompanying the spinodal decomposition is clearly confirmed as in the case of no treatment. As a result, it was confirmed that most of the oxygen was present in the Al portion.

The present inventor fabricated the following thin film laminate on a silicon substrate for the purpose of observing the phase separation state of the Al ₉₀ Ag ₁₀ (atomic%) film in this example with a planar TEM. did.

Si (1) / 5nmTa (1) / 200nmCu (1) / 5nmTa (2) / 2nmRu (2) / 15nmPtMn (3) / 4nmCoFe (4) / 1nmRu (4) / 4nmCoFe (4) / [0.2nmCu ( 5B) / 50 nm AlAg (9)

The sample thus fabricated was subjected to the same heat treatment as that of the magnetoresistive element film, and then subjected to planar TEM observation and composition analysis by nano-EDX.

  FIG. 13 is a photograph showing the result of TEM observation. That is, this figure is a limited-field electron diffraction image obtained from a range of 1 micrometer in diameter on the surface of the AlAg layer. Debye ring corresponding to the presence of the polycrystal is observed, and it can be seen that the AlAg layer is composed of other number of crystal grains.

  FIG. 14 is a TEM image of the AlAg layer. It is observed that the granular material A having a particle size of 30 to 200 nm that looks relatively black and the granular material B that has a particle size of 50 nm or less and looks white are separated.

  FIG. 15 is a HAADF (high angle annular dark field) image obtained by TEM observation for the same sample. In this figure, the part that appears black corresponds to the granular material B in FIG. 13B, and the part that appears white corresponds to the granular material A in FIG.

In these TEM images, the granular material A and the granular material B were subjected to composition analysis by nano-EDX. The granular material A was an Ag-rich phase of Al ₄₀ Ag ₆₀ [atomic%], and the granular material B was Al It was found to be an Al-rich phase of ₉₅ Ag ₅ [atomic%]. That is, it was confirmed that Al ₉₀ Ag _{10 as the base} material was separated into an Ag-rich granule A and an Al-rich granule B.

  FIG. 16 is a limited-field electron beam diffraction image obtained from the Ag-rich granule A. FIG. As can be seen from the figure, a diffraction image in which clear diffraction spots are regularly arranged was obtained, and it was found that the granular material A was composed of almost single crystal grains and the crystallinity was also good.

From this, the phase separation layer is Ag-rich phase D2 (region 9B) with high conductivity by spinodal decomposition and oxidation treatment, and the oxide insulator phase D1 (Al 9 O) close to Al ₂ O ₃ by oxidation treatment. In addition to the presence of the region 9A), it is confirmed by plane TEM observation that the respective phases are neatly distributed in the film plane by spinodal decomposition, and the occupied area of the Ag phase is about 10%. Met.

  That is, as can be seen from FIG. 15, the area occupied by the Ag-rich granular material A was about 10% of the whole.

On the other hand, when an Al ₈₀ Ag ₂₀ (x = 20) alloy was used as the base material, the following values were obtained as the magnetoresistive effect MR and the area resistance RA after the oxidation treatment.

Material of phase separation layer 9 MR RA
Al ₈₀ Ag ₂₀ (with oxidation treatment) 4.5% 0.17Ωμm ²

In an AlAg alloy, when the Ag ratio is less than 1%, the area resistance RA per square micron increases to 1 Ωμm ² or more because the region of the high conductive phase is significantly small, which is caused by the high resistance similar to TMR. Noise and frequency response will be reduced. On the other hand, if the ratio of Ag exceeds 40%, the region of the high conductive phase is too wide and the current confinement effect can no longer be obtained, and the low R and low AR are the same as when using a metal intermediate layer such as Cu. End up. The composition x is preferably in the range of 1 atomic% to 40 atomic% Ag, and the optimal composition can be appropriately determined depending on the required magnetoresistance effect MR and resistance value R. In addition, the case of using a base material in which Al is replaced with magnesium (Mg), silicon (Si), and manganese (Mn) was also examined, but some differences were observed in MR and R, its effects and cross-sectional TEM. The same tendency as in the case of Al was observed in the structure.

  Further, as illustrated in FIG. 10, even if a phase separation layer in which this Al—Ag alloy phase separation layer and a phase separation layer using a Cr—Cu alloy as a base material are used is used, Ag and Cr of the Al—Ag alloy are used. -Cu of Cu alloy played the role of a current path, and the same effect was acquired.

(Second embodiment)
Next, as a second embodiment of the present invention, a magnetoresistive effect element utilizing spinodal decomposition of aluminum (Al) -gold (Au) system will be described.

  Also in this example, the magnetoresistive effect element shown in FIG. 1 was manufactured. However, in this embodiment, the magnetization pinned layer 4 has a so-called “synthetic structure”.

In addition, the production method of the present example was substantially the same as the method described above with respect to the first example. However, the phase separation layer 9 was formed while irradiating the substrate with an ion beam containing oxygen ions simultaneously with the film formation. The film thickness and material of each layer constituting the magnetoresistive effect element are as follows. In addition, the code | symbol represented in FIG. 1 was attached | subjected in parenthesis to each corresponding layer.

Si substrate (1) / 5nmTa (2) / 200nmCu (2) / 5nm (Ni0.8Fe0.2) 78Cr22 (2) / 10nmPtMn (3) /2.5nmCoFe (4) /0.9nmRu (4) / 2. 5 nm CoFe (4) /0.2 nm Cu (5A)) / 0.8 nm AlAu alloy (9) /0.2 nm Cu (5B) / 3 nm CoFe (6) / 2 nm Ta (7) / 200 nm Cu (8)

The magnetoresistive effect MR and the sheet resistance R were as follows when Al ₉₀ Au ₁₀ alloy was used as the base material of the phase separation layer 9.

MR RA
With oxidation treatment 7.5% 0.18Ωμm ²

Further, the crystallinity of a sample with or without oxidation treatment of the phase separation layer 9 with the composition x = 0, 5, 10, 20, 40 atomic% of the Al _100-x Au _x alloy was examined by cross-sectional TEM observation. In the case of no treatment, it was confirmed that the phase separation between Al and about 1.5 nm Au accompanying spinodal decomposition was unclear. On the other hand, in the case of treatment, the phase separation between Al and width about 1.5 nm Au accompanying spinodal decomposition was clearly confirmed as in the case of no treatment, and oxygen analysis was performed on each phase. It was also confirmed that it exists in the part.

Therefore, the phase separation layer is separated into a highly conductive pure metal Au and an oxide insulator close to Al ₂ O ₃ by spinodal decomposition and oxidation treatment, and each phase is separated by spinodal decomposition. It was confirmed by flat TEM that the film was finely distributed in the film surface, and the occupied area of the Au phase was about 10%.

Further, when Al ₈₀ Au ₂₀ alloy (x = 20) was used as a base material, the magnetoresistance effect MR and the area resistance RA were as follows.

MR RA
With oxidation treatment 5.5% 0.13Ωμm ²

As described above, even in the AlAu alloy, when the proportion of Au is less than 1%, the area resistance RA per square micron is increased to 1 Ωμm ² or more because the region of the high conductive phase is significantly small, which is the same as that of TMR. Noise and frequency responsiveness due to the resistance are degraded. On the other hand, if the proportion of Au exceeds 40%, the region of the high conductive phase is too wide and the current confinement effect can no longer be obtained, and the low R and low AR are the same as when using a metal intermediate layer such as Cu. End up.

  Further, a part of Al is magnesium (Mg), calcium (Ca), silicon (Si), germanium (Ge), boron (B), tantalum (Ta), tungsten (W), niobium (Nb), zirconium (Zr). ), Titanium (Ti), chromium (Cr), zinc (Zn), lithium (Li), and gallium (Ga) were also examined, but almost the same effect was obtained depending on the amount of substitution. .

  Considering application to an actual head, the composition can be appropriately determined in the range of 1 atomic% to 40 atomic% Au depending on the required magnetoresistance effect MR and resistance value R.

(Third embodiment)
Next, as a third embodiment of the present invention, a magnetoresistive element utilizing spinodal decomposition of a copper (Cu) -nickel (Ni) -iron (Fe) system will be described.

  Also in this example, a magnetoresistive effect element having a cross-sectional structure similar to that of FIG. 1 was manufactured. However, the interface adjustment layer 5B was not provided. In this embodiment, the magnetization pinned layer 4 has a so-called “synthetic structure”.

The production method of this example was substantially the same as the method described above with respect to the first example. The film thickness and material of each layer constituting the magnetoresistive effect element are as follows. In addition, the code | symbol represented in FIG. 1 was attached | subjected in parenthesis to each corresponding layer.

Si substrate (1) / 5nmTa (2) / 200nmCu (2) / 5nm (Ni0.8Fe0.2) 78Cr22 (2) / 10nmPtMn (3) /2.5nmCoFe (4) /0.9nmRu (4) / 2. 5 nm CoFe (4) /0.8 nm CuNiFe alloy (9) /2.0 nm Cu (5) / 3 nm CoFe (6) / 2 nm Ta (7) / 200 nm Cu (8)

Here, the CuNiFe alloy used as the base material of the phase separation layer 9 has a composition formula represented by Cu _x (Ni _1-y Fe _y ) _100-x (atomic%), and x = 0.5, 1, 10 20, 50, 60, y = 0, 0.2, 0.5, 0.7. A magnetic coupling blocking layer 5 made of 2.0 nm Cu was inserted between the phase separation layer 9 and the magnetization free layer 6. The magnetic coupling blocking layer 5 needs to have a thickness that blocks the magnetic coupling between the phase separation layer 9 made of CuNiFe alloy and the magnetization free layer 6, and the optimum film thickness is 1 to About 3 nm is desirable.

  In forming the phase separation layer 9, the substrate was deposited while irradiating the substrate with an ion beam containing oxygen ions at the same time as the film formation.

For comparison, a magnetoresistive element provided with an alloy layer having a composition of Cu ₂₀ (Ni _0.8 Fe _0.2 ) ₈₀ (atomic%) instead of the phase separation layer 9 was also prepared.

  After formation of the element, a heat treatment was performed at 300 ° C. for 10 hours by applying a magnetic field of 5 kilo-Oersted (kOe) in a vacuum.

  Further, when the magnetoresistive effect MR and the resistance value R were examined for these magnetoresistive effect elements, the magnetoresistive effect MR was 3 except for x = 0.1, 60, and y = 0.7. 10%, and the resistance value R was also 0.15 to 1.0 [Ω]. On the other hand, when x = 5, 60 and y = 0.7, the MR is 0.5% or less, the RA is very small, and the characteristics are not suitable for practical use. I understood. Further, Au, Ag, Pt, Pd, Ir, Os and the like other than Cu were examined as the magnetic shielding layer 5, and almost the same magnetic shielding effect was confirmed.

  On the other hand, in this example, it was also found that even when the magnetization pinned layer 4 was slightly oxidized, the characteristics of the magnetoresistive element were hardly deteriorated.

  Furthermore, although the magnetoresistive effect element in the case where the magnetic coupling blocking layer 5 is not formed is produced, the magnetic field responsiveness of the magnetization free layer 6 is deteriorated due to the influence of the phase separation layer 9 having some magnetism, and therefore the MR sensitivity. Decreased.

  From the above results, it is possible to obtain a magnetoresistive element having good characteristics by using an alloy having a composition region that achieves both spinodal decomposition and oxidation of the Ni—Fe phase by using the base material of the phase separation layer 9 and the magnetic coupling blocking layer 5. It turns out that it becomes possible to provide.

_Furthermore, in the _{Cu x (Ni 1-y Fe} y) composition formula of _100-x (atomic%), but was also examined some magnetoresistance effect element using an alloy obtained by replacing the Fe portion to Co, Cu _x Almost the same results as (Ni _1-y Fe _y ) _100-x (atomic%) were obtained.

Furthermore, as illustrated in FIG. 10, a phase in which this Cu _x (Ni _1-y Fe _y ) _100-x (atomic%) phase separation layer and a phase separation layer using an Al—Ag alloy as a base material are combined. The same effect was obtained even when the separation layer was used.

(Fourth embodiment)
Next, as a fourth embodiment of the present invention, a magnetoresistive effect element provided with a phase separation layer of two magnetization layers will be described.

  17 and 18 are schematic views showing the cross-sectional structure of the magnetoresistive element of this example. Also in this figure, the same elements as those described above with reference to FIGS. 1 to 16 are denoted by the same reference numerals, and detailed description thereof is omitted.

  That is, in the structure of FIG. 17, the phase separation layer 9 is inserted not only in the spacer layer portion but also in the magnetization pinned layer 4.

  In the structure of FIG. 18, the phase separation layer 9 is inserted not only in the spacer layer portion but also in the magnetization free layer 6.

The production method of this example was also substantially the same as the method described above with respect to the first example. The thickness and material of each layer constituting the magnetoresistive effect element shown in FIG. 17 are as follows. In addition, the code | symbol represented in FIG. 17 was attached | subjected in parenthesis to each corresponding layer.

Si substrate (1) / 5 nm Ta (2) / 200 nm Cu (2) / 5 nm (Ni0.8Fe0.2) 78Cr22 (2) / 10 nm PtMn (3) / 2 nm CoFe (4) /0.5 nm CuNiFe alloy (9) /2.5 nm CoFe (4) /0.5 nm Cu (5) /0.8 nm CuNiFe alloy (9) / 3 nm CoFe (6) / 2 nm Ta (7) / 200 nm Cu (8)

Further, the thickness and material of each layer constituting the magnetoresistive effect element shown in FIG. 18 are as follows. In addition, the code | symbol represented in FIG. 18 was attached | subjected in parenthesis to each corresponding layer.

Si substrate (1) / 5nmTa (2) / 200nmCu (2) / 5nm (Ni0.8Fe0.2) 78Cr22 (2) / 10nmPtMn (3) / 4nmCoFe (4) /0.2nmCu (5) /0.8nmCuNiFe alloy (9) / 1 nm Cu (5) / 1 nm CoFe (6) /0.3 nm AlAg alloy (9) / 3 nm NiFe
(6) / 2 nm Ta (7) / 200 nm Cu (8)

For all the elements, the production method was substantially the same as the method described above with respect to the first embodiment. However, the magnetic phase separation layer 9 between the magnetization fixed layer 4 and the magnetization free layer 6 was formed by oxidation by irradiation with an ion beam containing oxygen ions after film formation. Further, the phase separation layer 9 inserted into the magnetization fixed layer 4 and the magnetization free layer 6 was formed while irradiating the substrate with an ion beam containing oxygen ions simultaneously with the film formation.

Moreover, CuNiFe which is a base material of the phase separation layer 9 has a composition formula represented by Cu _x (Ni _100-y Fe _y ) _100-x (atomic%), and a composition x = 1, 10, 20, 50, y. = 0, 0.2, 0.5, and the AlAg alloy is formed of Al ₉₀ Ag ₁₀ (atomic%), respectively.

  After sample preparation, a magnetic field of 5 (kOe) was applied in a vacuum, and heat treatment was performed at 300 ° C. for 10 hours.

  As a result of evaluating the characteristics of the magnetoresistive effect element thus produced, a good magnetoresistance change MR and resistance value R substantially equal to those of the third example were obtained. In addition, the same good characteristics were obtained for both the structure of FIG. 17 and the structure of FIG.

On the other hand, when Al ₉₀ Au ₁₀ was used as the base material of the phase separation layer 9, the same good characteristics were obtained.

(Fifth embodiment)
Next, a magnetoresistive effect element combining the first embodiment and the second embodiment will be described as a fifth example of the present invention.

  FIG. 19 is a schematic diagram showing a cross-sectional structure of the magnetoresistive element of this example. Also in this figure, the same elements as those described above with reference to FIGS. 1 to 18 are denoted by the same reference numerals, and detailed description thereof is omitted.

  That is, the structure of the present embodiment has a so-called “top type” laminated structure in which the magnetization free layer 6 is provided on the lower side when viewed from the substrate electrode 1 side. In this stacked structure, phase separation layers 9-3 and 9-4 are provided in the spacer layer, and the phase separation layers 9-1 and 9 are also provided between the electrode 1 and the magnetization free layer 6. -2 is inserted.

The film thickness and material of each layer constituting the magnetoresistive effect element of this example are as follows. In addition, the code | symbol represented in FIG. 19 was attached | subjected in parenthesis to each corresponding layer.

Si substrate (1) / 3nmTa (2) / 200nmCu (2) / 2nmAl70Ag30 alloy (9-1) /0.8nmCr80Cu20 alloy (9-2) / 4nmCo90Fe10 (6) / 1nmAl70Cu30 alloy (9-3) / 1nmCu20Ni40Co20 alloy ( 9-4) /0.5 nm Cu (5) / 4 nm Co90Fe10 (4) / 15 nm PtMn (3) / 2 nmRu (7) / 200 nmCu (8)

In addition, the production method of the present example was substantially the same as the method described above with respect to the first example. As the oxidation treatment of the phase separation layers 9-1, 9-2, and 9-3, after forming the base material into a film, oxygen at a flow rate of 4 SCCM with oxygen energy at an acceleration voltage of 100 volts (V) at an RF power of 50 watts (W) For about 30 seconds. However, the CuNiCo alloy of the phase separation layer 9-4 is subjected to oxidation treatment at a RF power of 70 W in the same manner as described above after promoting the spinodal decomposition by low energy Ar ion irradiation after the deposition of the base material. gave.

The magnetic characteristics after heat treatment of the element manufactured with such a film configuration are as follows: the area resistance per square micron area is 350 (mΩ · μm ² ), and the magnetoresistance change rate is 5.5%. As a result, it was confirmed that the magnetoresistive effect element was sufficiently adaptable to an actual head.

(Sixth embodiment)
Next, as a sixth example of the present invention, a magnetoresistive effect element combining the first embodiment and the second embodiment will be described as in the fifth example.

  FIG. 20 is a schematic diagram showing a cross-sectional structure of the magnetoresistive element of this example. Also in this figure, the same elements as those described above with reference to FIGS. 1 to 19 are denoted by the same reference numerals, and detailed description thereof is omitted.

  That is, the structure of the present embodiment has a so-called “bottom type” laminated structure in which the magnetization pinned layer 4 is provided on the lower side when viewed from the substrate electrode 1 side. Also in this laminated structure, the phase separation layers 9-1 and 9-2 are provided in the spacer layer portion, and the phase separation layers 9-3 and 9-4 are also provided between the magnetization free layer 6 and the electrode 8. Has been inserted.

The film thickness and material of each layer constituting the magnetoresistive effect element of this example are as follows. In addition, the code | symbol represented in FIG. 20 was attached | subjected in parenthesis to each corresponding layer.

Si substrate (1) / 5 nm Ta (2) / 2 nm Ru (2) / 15 nm PtMn (3) / 4 nm Co ₉₀ Fe ₁₀ (4) / 1 nm CuNiFe alloy (9-1) /0.7 nm Al ₇₀ Cu ₃₀ alloy (9-2) / 0.2 nm Cu (5) / 4 nm Co ₉₀ Fe ₁₀ (6) /0.5 nm Al ₈₀ Au ₂₀ alloy (9-3) / 1 nm Al ₇₀ Cu ₃₀ alloy (9-4) / 200 nm Cu (8)

In addition, the creation method of the present example was substantially the same as the method described above with respect to the fifth example.

The magnetic characteristics after heat treatment of an element manufactured with such a film structure are as follows: area resistance per square micron area is 250 (mΩ · μm ² ), and the amount of change in area resistance per square micron area corresponding to the magnetic head output. (AΔR) was as large as 25 (mΩ · μm ² ), and it was confirmed that the magnetoresistive effect element was sufficiently adaptable to an actual head.

(Seventh embodiment)
Next, as a seventh embodiment of the present invention, a magnetoresistive effect element using an aluminum (Al) -silver (Ag) -tantalum (Ta) system and an aluminum (Al) -copper (Cu) system will be described. .

  Also in this example, the magnetoresistive effect element shown in FIG. 1 was manufactured. However, in this embodiment, the magnetization pinned layer 4 has a so-called “synthetic structure”.

In addition, the production method of the present example was substantially the same as the method described above with respect to the first example. However, in forming the phase separation layer 9, after the film formation, phase separation was performed by irradiating argon ions with an accelerating voltage of 50 V and an input power of 50 W, and then oxidizing treatment while irradiating an ion beam containing oxygen ions. Further, after the magnetoresistive effect element was formed, a heat treatment in a magnetic field at 270 ° C. for 10 hours was performed in order to improve the magnetic characteristics. The film thickness and material of each layer constituting the magnetoresistive effect element are as follows. In addition, the code | symbol represented in FIG. 1 was attached | subjected in parenthesis to each corresponding layer.

Si substrate (1) / 5nmTa (2) / 200nmCu (2) / 5nm (Ni0.8Fe0.2) 78Cr22 (2) / 10nmPtMn (3) /3.5nmCoFe (4) /1.0nmRu (4) / 3. 5 nm CoFe (4) /0.2 nm Cu (5A)) / 1.1 nm AlAgTa alloy (9) /0.5 nm Cu (5B) /3.5 nm CoFe (6) / 2 nm Ru (7) / 200 nm Cu (8)

(Al ₈₀ Ta ₂₀ ) ₈₀ Ag ₂₀ alloy was used as the base material of the phase separation layer 9.
In producing this magnetoresistive effect element, the Si substrate (1) / 5 nm Ta (2) / 10 nm PtMn (3) /3.5 nm CoFe (4) under the same conditions as the phase separation layer 9 of (Al ₈₀ Ta ₂₀ ) ₈₀ Ag ₂₀ alloy. ) A 0.2 nm Cu (5A)) / 1.1 nm AlAgTa alloy (9) is laminated twice to form a sample subjected to heat treatment, and the form of the phase separation layer 9 is a plane TEM, a cross-sectional TEM, a composition and its distribution. Were examined by SIMS (Secondary ion mass spectroscopy).

As a result, the form of the phase separation layer 9 was a structure close to the schematic diagram shown in FIG. Specifically, a silver (Ag) phase 9B (D2) having a particle size of 2 to 3 nm, which has been spinodal decomposed from planar TEM and SIMS, has a high purity, an oxide insulator phase 9A (D1) close to Al ₂ O ₃ and Ta _The oxide insulator phase 9A (D2) close to ₂ O ₅ is formed, and the high silver (Ag) phase 9B from the cross-section TEM is columnar in the film thickness direction, so that a good current path is formed. Were confirmed together.
Moreover, as a result of preparing and evaluating a sample having the same layer structure and using an Al—Cu alloy as a base material of the phase separation layer 9, a phase separation structure similar to the case of using AlAgTa was observed. The Al—Cu based alloy causes phase separation in the composition region of Al ₇₀ Cu ₃₀ . Therefore, Al ₇₀ Cu ₃₀ may be used as the base material (9). However, since Cu diffuses from the Cu layer (4) stacked vertically to the phase separation layer (9), the composition of the base material is as follows: A material having a Cu composition lower than that of Al ₇₀ Cu ₃₀ may be used.

The magnetic characteristics after heat treatment of the element manufactured with such a film structure are as follows. The electric resistance per unit area is 250 (mΩ · μm ² ) in both the sample using Al—Ag—Ta and the sample using Al—Cu. The magnetoresistance change rate was 6.5%, and good characteristics were obtained. It was confirmed that the magnetoresistive element was sufficiently adaptable to an actual head.

(Eighth embodiment)
Next, a magnetoresistive element using phase separation of an iron (Fe) -magnesium (Mg) alloy will be described as an eighth embodiment of the present invention.

  Also in this example, a magnetoresistive effect element having the same laminated structure as that shown in FIG. 1 was manufactured. However, in this embodiment, the magnetization pinned layer 4 has a so-called “synthetic structure”.

In addition, the production method of the present example was substantially the same as the method described above with respect to the first example. However, the phase separation layer 9 was formed while irradiating the substrate with an ion beam containing oxygen ions simultaneously with the film formation. The film thickness and material of each layer constituting the magnetoresistive effect element are as follows. In addition, the code | symbol represented in FIG. 1 was attached | subjected in parenthesis to each corresponding layer.

Si substrate (1) / 5 nm Ta (2) / 200 nm Cu (2) / 5 nm (Ni _0.8 Fe _0.2 ) ₇₈ Cr ₂₂ (2) / 10 nm PtMn (3) /2.5 nm CoFe (4) /0.9 nm Ru ( 4) /2.5 nm CoFe (4) /0.5 nm Cu (5A)) / 1.0 nm FeMg alloy (9) /1.0 nm Cu (5B) / 3 nm CoFe (6) / 2 nm Ta (7) / 200 nm Cu (8)

The magnetoresistive effect MR and the sheet resistance RA were as follows when Mg ₉₀ Fe ₁₀ alloy was used as the base material of the phase separation layer 9.

MR RA
With oxidation treatment 8.0% 0.25Ωμm ²

_Further, for the presence of the oxidation process of the phase separation layer 9 for using the composition x = 0,5,10,20,40 atomic% of _{Mg 100-x} Fe x alloy, to create each sample, the crystal cross-section TEM observation I examined the sex. In the case of no oxidation treatment, it was confirmed that the phase separation between Mg and the width of about 2 nm Fe accompanying phase decomposition was unclear. On the other hand, in the case with oxidation treatment, the phase separation between Mg and width of about 2 nm Fe accompanying the phase decomposition was clearly confirmed in the same manner as in the case without treatment. It was confirmed that most of the oxygen was present in the Mg phase, although some oxygen was observed in the sample.

  That is, it was confirmed that the phase separation layer 9 was phase-separated into a highly conductive pure metal Fe phase and an oxide insulator phase close to MgO by spinodal decomposition and oxidation treatment. As a result of planar TEM observation, it was found that the respective phases were neatly separated and distributed in the film plane by spinodal decomposition, and the occupied area of the Fe phase was about 10%.

On the other hand, when the Mg ₈₀ Fe ₂₀ alloy (x = 20) was used as the base material, the magnetoresistance effect MR and the sheet resistance RA were as follows.

MR RA
With oxidation treatment 6.5% 0.2Ωμm ²

Also, in the FeMg-based alloy, when the Fe content is less than 1%, the area resistance RA per square micron is increased to 1 Ωμm ² or more because the region of the high conductive phase is significantly small, which is the same as that of TMR. Noise and frequency responsiveness due to the resistance are degraded.
On the other hand, if the proportion of Fe exceeds 40%, the region of the high conductive phase is too wide and the current confinement effect can no longer be obtained, and both R and AR decrease as in the case of using a metal intermediate layer such as Cu. End up. Therefore, it is desirable that the Fe composition be in the range of 1 atomic% to 40 atomic%.

  Further, a part of Mg of the FeMg alloy is made of aluminum (Al), calcium (Ca), silicon (Si), germanium (Ge), boron (B), tantalum (Ta), tungsten (W), niobium (Nb), An alloy system in which zirconium (Zr), titanium (Ti), hafnium (Hf), chromium (Cr), zinc (Zn), lithium (Li) or gallium (Ga) is substituted, and a part of Fe is nickel (Ni ) Or an alloy system substituted with cobalt (Co), it was found that substantially the same effect can be obtained by appropriately adjusting the amount of substitution.

  On the other hand, instead of Mg in the FeMg alloy, molybdenum (Mo), calcium (Ca), titanium (Ti), zirconium (Zr), niobium (Nb), hafnium (Hf), tantalum (Ta), boron (B), Similar effects were obtained when aluminum (Al) or silicon (Si) was used.

  Considering application to an actual magnetic head, the composition of Fe in the FeMg-based alloy can be appropriately determined in the range of 1 atomic% to 40 atomic% according to the required magnetoresistance effect MR and resistance value R. .

(Ninth embodiment)
Next, a magnetoresistive element utilizing phase separation of an aluminum (Al) -nickel (Ni) alloy will be described as a ninth embodiment of the present invention.

  Also in this example, a magnetoresistive effect element having a cross-sectional structure similar to that of FIG. 1 was manufactured. However, the interface adjustment layer 5B was not provided. In this embodiment, the magnetization pinned layer 4 has a so-called “synthetic structure”.

The production method of this example was also substantially the same as the method described above with respect to the first example. The film thickness and material of each layer constituting the magnetoresistive effect element are as follows. In addition, the code | symbol represented in FIG. 1 was attached | subjected in parenthesis to each corresponding layer.

Si substrate (1) / 5 nm Ta (2) / 200 nm Cu (2) / 5 nm (Ni _0.8 Fe _0.2 ) ₇₈ Cr ₂₂ (2) / 10 nm PtMn (3) /2.5 nm CoFe (4) /0.9 nm Ru ( 4) /2.5 nm CoFe (4) /1.2 nm AlNi alloy (9) /2.0 nm Cu (5) / 3 nm CoFe (6) / 2 nm Ta (7) / 200 nm Cu (8)

Here, the AlNi alloy used as the base material of the phase separation layer 9 has a composition formula represented by Al _100-x Ni _x (atomic%), and x = 0.5, 1, 10, 20, 50, 60, It was. A magnetic coupling blocking layer 5 made of 2.0 nm Cu was inserted between the phase separation layer 9 and the magnetization free layer 6. The magnetic coupling blocking layer 5 needs to have a thickness sufficient to block the magnetic coupling between the phase separation layer 9 made of an AlNi alloy and the magnetization free layer 6, and the optimum film thickness is 1 to About 3 nm is desirable.

  In forming the phase separation layer 9, the substrate was deposited while irradiating the substrate with an ion beam containing oxygen ions at the same time as the film formation.

  After formation of the element, a heat treatment was performed at 300 ° C. for 10 hours by applying a magnetic field of 5 kilo-Oersted (kOe) in a vacuum.

  Further, when the magnetoresistive effect MR and the resistance value R of these magnetoresistive effect elements were examined, the magnetoresistive effect MR was 3 to 10% except for x = 0.1 and 60, and the resistance value R was also R. It was 0.15 to 1.0 [Ω] and good characteristics. On the other hand, when x = 5, 60, the MR was 0.5% or less, the AΔR was very small, and the characteristics were not suitable for practical use. As a result of investigating not only Cu but also gold (Au), silver (Ag), platinum (Pt), palladium (Pd), iridium (Ir), and osmium (Os) as a material of the magnetic coupling blocking layer 6, A similar magnetic shielding effect was confirmed.

  On the other hand, in this example, it was also found that even when the magnetization pinned layer 4 was slightly oxidized, the characteristics of the magnetoresistive element were hardly deteriorated.

  Furthermore, although a magnetoresistive effect element having a structure in which the magnetic coupling blocking layer 5 is not formed is produced, the magnetic field responsiveness of the magnetization free layer 6 deteriorates due to the influence of the phase separation layer 9 having some magnetism, and therefore MR sensitivity. Decreased.

  From the above results, by using the phase separation layer 9 made of an alloy having a composition region that achieves both spinodal decomposition and oxidation of the Al—Ni phase as a base material, and further providing the magnetic coupling blocking layer 5, good characteristics can be obtained. It has been found that a magnetoresistive element can be provided.

Furthermore, in an alloy system represented by the composition formula Al _100-x Ni _x (atomic%), a magnetoresistive effect element using an alloy in which the Ni portion is replaced with Co or Fe was also examined. Al _100-x A result almost similar to that of Ni _x (atomic%) was obtained.

  Also, instead of Al, molybdenum (Mo), magnesium (Mg), tungsten (W), titanium (Ti), zirconium (Zr), niobium (Nb), hafnium (Hf), tantalum (Ta), boron (B) Alternatively, when silicon (Si) was used, the same effect as Al was obtained.

Further, as illustrated in FIG. 10, a phase separation layer in which a phase separation layer made of this Al _100-x Ni _x (atomic%) alloy and a phase separation layer obtained using an Al—Ag alloy as a base material are combined. Even when used, the same effect was obtained.

(Tenth embodiment)
Next, a magnetoresistive element using phase separation of an aluminum (Al) -cobalt (Co) alloy will be described as a tenth embodiment of the present invention.

  Also in this example, a magnetoresistive effect element having a cross-sectional structure similar to that of FIG. 1 was manufactured. However, the interface adjustment layer 5B was not provided. Also in this embodiment, the magnetization pinned layer 4 has a so-called “synthetic structure”.

The production method of this example was also substantially the same as the method described above with respect to the first example. The film thickness and material of each layer constituting the magnetoresistive effect element are as follows. In addition, the code | symbol represented in FIG. 1 was attached | subjected in parenthesis to each corresponding layer.

Si substrate (1) / 5 nm Ta (2) / 200 nm Cu (2) / 5 nm (Ni _0.8 Fe _0.2 ) ₇₈ Cr ₂₂ (2) / 10 nm PtMn (3) /2.5 nm CoFe (4) /0.9 nm Ru ( 4) /2.5 nm CoFe (4) /1.0 nm AlCo alloy (9) /2.0 nm Cu (5) / 3 nm CoFe (6) / 2 nm Ta (7) / 200 nm Cu (8)

Here, the AlCo alloy used as the base material of the phase separation layer 9 has a composition formula represented by Al _100-x Co _x (atomic%), and x = 0.5, 1, 10, 20, 50, 60, It was. A magnetic coupling blocking layer 5 made of 2.0 nm Cu was inserted between the phase separation layer 9 and the magnetization free layer 6. The magnetic coupling blocking layer 5 needs to have a thickness sufficient to block magnetic coupling between the phase separation layer 9 made of an AlCo alloy and the magnetization free layer 6, and the optimum film thickness is 1 to About 3 nm is desirable.

  In forming the phase separation layer 9, the substrate was deposited while irradiating the substrate with an ion beam containing oxygen ions at the same time as the film formation.

  After forming the device, a magnetic field of 10 kilo Oersted (kOe) was applied in a vacuum and heat treatment was performed at 300 ° C. for 10 hours.

  Further, when the magnetoresistive effect MR and the resistance value R of these magnetoresistive effect elements were examined, the magnetoresistive effect MR was 3 to 10% except for x = 0.1 and 60, and the resistance value R was also R. It was 0.15 to 1.0 [Ω] and good characteristics. On the other hand, when x = 5, 60, the MR was 0.5% or less, the AΔR was very small, and the characteristics were not suitable for practical use. As a result of investigating gold (Au), silver (Ag), platinum (Pt), palladium (Pd), iridium (Ir), and osmium (Os) other than Cu as the magnetic blocking layer 5, almost the same magnetic properties were obtained. The blocking effect was confirmed.

  On the other hand, in this example, it was also found that even when the magnetization pinned layer 4 was slightly oxidized, the characteristics of the magnetoresistive element were hardly deteriorated.

  Furthermore, although a magnetoresistive effect element having a structure in which the magnetic coupling blocking layer 5 is not provided is produced, the magnetic field responsiveness of the magnetization free layer 6 deteriorates due to the influence of the phase separation layer 9 having some magnetism, and therefore MR sensitivity. Decreased.

  From the above results, it is possible to use the phase separation layer 9 made of an alloy having a composition region that achieves both spinodal decomposition and oxidation of the Al—Co phase as a base material, and further to provide a magnetic coupling blocking layer 5 so that magnetic properties with good characteristics can be obtained. It has been found that a resistance effect element can be provided.

Furthermore, in the alloy system represented by the composition formula Al _100-x Co _x (atomic%), a magnetoresistive effect element using an alloy in which the Co portion is replaced with Ni or Fe was also examined. As a result, Al _100-x A result almost similar to Co _x (atomic%) was obtained.

  Also, instead of Al, molybdenum (Mo), magnesium (Mg), tungsten (W), titanium (Ti), zirconium (Zr), niobium (Nb), hafnium (Hf), tantalum (Ta), boron (B) When chromium (Cr) or vanadium (V) was used, the same effect as Al was obtained.

(Eleventh embodiment)
Next, as an eleventh embodiment of the present invention, “specularity dGs” in the case where an AlAg-based alloy represented by the composition formula Al _100-x Ag _x is used as the phase separation layer has the following film configuration. It was calculated from the magnetoresistance change rate (CIP-MR) in the film surface and the specific resistance (Rs) of the film. The specularity dGs (1 / Ω) is one index representing the specular reflectivity of electrons, and in the CIP type MR, the MR change rate tends to increase as this value increases. In addition, the specularity dGs has a slightly different absolute value depending on the film configuration, but its tendency (for example, superiority of the film quality of the electron reflecting layer, etc.) is hardly different.

Film number after the substrate _{/Ta5/Ru2/PtMn15/CoFe2/Ru1.0/CoFe2/Cu2.5/CoFe2/Cu0.2/Al 100-x Ag x 1.0 /} Cu0.2 / Ru2 ( element symbol Represents thickness and its unit is nanometer.)

The composition x in the alloy system Al _100-x Ag _x constituting the phase separation layer is in the range of 0, 2, 10, 20, 30, 40, 50, and heat treatment in a magnetic field at 270 ° C. for 10 hours after film formation. gave. The magnetoresistance change rate of the obtained magnetoresistive effect element was measured, and the specularity dGs was evaluated.

FIG. 21 is a graph showing the relationship between the specularity dGs (× 10 ⁻³ : 1 / Ω) and the composition x.

As can be seen from the figure, the specularity dGs (× 10 ⁻³ : 1 / Ω) is 2.1 from the addition of a small amount of silver (Ag) to aluminum (Al) from zero to 2 atomic%. Increases significantly to 3.1. When the addition amount of silver (Ag) with respect to aluminum (Al) is further increased, the specularity dGs (× 10 ⁻³ : 1/1) is obtained in the vicinity of 20 atomic%, which is the composition region most easily spinodal decomposition in this Al—Ag alloy. Ω) peaked at about 4.3. When the addition amount of silver (Ag) is further increased, the specularity dGs decreases again, and when it exceeds 40 atomic%, the specularity dGs becomes 3.0 (× 10 ⁻³ : 1 / Ω) or less.

  The specularity dGs promotes further phase separation by oxidation treatment, ion irradiation, etc. for the Al-Ag phase separation material that changes in this way with respect to the composition x, and forms a low resistance phase to form a CPP type. When the element is created, the element characteristics as described above as the first embodiment can be obtained. In other words, the result of investigating the dependency of specularity dGs and MR on the composition x in a state where the oxidation treatment and the phase separation treatment are not performed using the CIP type MR element, and the MR and RA using the CPP type element. The result of examining the dependence on the composition x was generally consistent.

According to the results of the inventor's trial production, a material having a composition range in which the specularity dGs is 3.0 (× 10 ⁻³ : 1 / Ω) or more is used as the current confinement layer of the CPP element by the above-described method. There was a tendency to obtain an element with excellent characteristics.

(Twelfth embodiment)
Next, as a twelfth embodiment of the present invention, a BMR (ballistic magnetoresistance effect) type resistance effect element formed by providing a magnetic phase separation layer between a pair of ferromagnetic layers will be described.

FIG. 22 is a schematic diagram showing the cross-sectional structure of the main part of the magnetoresistive effect element manufactured in this example. The production method of this example was substantially the same as the method described above with respect to the first example. The film thickness and material of each layer constituting the magnetoresistive effect element are as follows. In addition, the code | symbol represented in FIG. 22 was attached | subjected in parenthesis to each corresponding layer.

_{Si (1) / 100nmSiO 2 (} 1) / 10nmTa (2) / 200nmCu (2) / 5nmTa (2) /2.5nmCoFe (6) /1.5nmNi 0.8 Fe 0.2 (6) / 5nmAl 0. ₈ Ni _0.2 (9) / 3 nm Co _0.9 Fe _0.1 (4) / 15 nm PtMn (3) / 5 nm Ta (8) / 200 nm Cu (8) / 100 Au (8)

After forming the laminated structure, a heat treatment was performed at 300 ° C. for 10 hours by applying a magnetic field of 10 kilo-Oersted (kOe) in a vacuum.

  An element on which an Al—Ni layer that was not subjected to phase separation and oxidation treatment was formed for comparison, and its element characteristics were also evaluated.

  When the MR change rate of this element was measured in a magnetic field of plus or minus 500 oersteds, the MR of this example subjected to phase separation and oxidation treatment showed a large MR change rate of about 20%, while these treatments were performed. The MR change rate of the sample of the comparative example that was not subjected to the above was 2% or less, and it was confirmed that the MR change rate was greatly increased by the present invention. The reason for this large increase in MR ratio is that nickel (Ni), which is a magnetic element of the provided phase separation layer 9, or a nickel-rich phase is in contact with the upper and lower magnetic layers 4 and 6 in a very small area. It is thought that was expressed.

  When the cross-sectional TEM of the device of this example was observed, an image was seen where the lattice image, which was thought to be Ni but was connected to the upper and lower magnetic layers, was observed, and this was considered to have caused BMR. It is done.

(Thirteenth embodiment)
Next, a magnetic reproducing apparatus equipped with the magnetoresistive element of the present invention will be described as a thirteenth embodiment of the present invention. That is, the magnetoresistive effect element or the magnetic head according to the embodiment of the present invention described above with reference to FIGS. 1 to 22 is incorporated into a recording / reproducing integrated magnetic head assembly and can be mounted on a magnetic recording / reproducing apparatus. .

  FIG. 23 is a main part perspective view illustrating a schematic configuration of such a magnetic recording / reproducing apparatus. That is, the magnetic recording / reproducing apparatus 150 according to the embodiment of the present invention is an apparatus using a rotary actuator. In the figure, a recording medium disk 200 is mounted on a spindle 152 and rotated in the direction of arrow A by a motor (not shown) that responds to a control signal from a drive device control unit (not shown). The magnetic recording / reproducing apparatus 150 according to the embodiment of the present invention may include a plurality of medium disks 200.

  A head slider 153 that records and reproduces information stored in the medium disk 200 is attached to the tip of a thin-film suspension 154. Here, the head slider 153 has, for example, the magnetoresistive effect element or the magnetic head according to any one of the above-described embodiments mounted near the tip thereof.

  When the medium disk 200 rotates, the medium facing surface (ABS) of the head slider 153 is held with a predetermined flying height from the surface of the medium disk 200. Alternatively, a so-called “contact traveling type” in which the slider contacts the medium disk 200 may be used.

  The suspension 154 is connected to one end of an actuator arm 155 having a bobbin portion for holding a drive coil (not shown). A voice coil motor 156, which is a kind of linear motor, is provided at the other end of the actuator arm 155. The voice coil motor 156 is composed of a drive coil (not shown) wound around the bobbin portion of the actuator arm 155, and a magnetic circuit composed of a permanent magnet and a counter yoke arranged so as to sandwich the coil.

  The actuator arm 155 is held by ball bearings (not shown) provided at two positions above and below the spindle 157, and can be freely rotated and slid by a voice coil motor 156.

  FIG. 24 is an enlarged perspective view of the magnetic head assembly ahead of the actuator arm 155 as viewed from the disk side. That is, the magnetic head assembly 160 includes an actuator arm 155 having, for example, a bobbin portion that holds a drive coil, and a suspension 154 is connected to one end of the actuator arm 155.

    A head slider 153 including any of the magnetoresistive elements described above with reference to FIGS. 1 to 22 is attached to the tip of the suspension 154. The suspension 154 has a lead wire 164 for writing and reading signals, and the lead wire 164 and each electrode of the magnetic head incorporated in the head slider 153 are electrically connected. In the figure, reference numeral 165 denotes an electrode pad of the magnetic head assembly 160.

  According to the present embodiment, the magnetoresistive effect element according to the embodiment of the present invention as described above with reference to FIGS. 1 to 22 is provided, so that magnetic recording is performed on the medium disk 200 at a higher recording density than before. Information can be read reliably.

(Fourteenth embodiment)
Next, as a fourteenth example of the present invention, a magnetic memory including the magnetoresistive effect element according to the embodiment of the present invention will be described. That is, by using the magnetoresistive effect element according to the embodiment of the present invention described with reference to FIGS. 1 to 22, for example, a magnetic memory such as a random access magnetic memory in which memory cells are arranged in a matrix form. realizable.

  FIG. 25 is a conceptual diagram illustrating the matrix configuration of the magnetic memory of this embodiment.

  That is, this figure shows a circuit configuration of the embodiment when memory cells are arranged in an array. In order to select one bit in the array, a column decoder 350 and a row decoder 351 are provided, and the switching transistor 330 is turned on by the bit line 334 and the word line 332 to be uniquely selected and detected by the sense amplifier 352. Thereby, the bit information recorded on the magnetic recording layer constituting the magnetoresistive effect element 321 can be read.

  The bit information is written by a magnetic field generated by supplying a write current to the specific write word line 323 and the bit line 322.

  FIG. 26 is a conceptual diagram showing another specific example of the matrix configuration of the magnetic memory of this embodiment. That is, in the case of this specific example, the bit lines 322 and the word lines 334 wired in a matrix are selected by the decoders 360 and 361, respectively, and specific memory cells in the array are selected. Each memory cell has a structure in which a magnetoresistive element 321 and a diode D are connected in series. Here, the diode D has a role of preventing the sense current from bypassing in the memory cells other than the selected magnetoresistance effect element 321.

  Writing is performed by a magnetic field generated by supplying a write current to the specific bit line 322 and the write word line 323, respectively.

  FIG. 27 is a conceptual diagram showing the cross-sectional structure of the main part of the magnetic memory according to the embodiment of the present invention. FIG. 28 is a cross-sectional view taken along line A-A ′ of FIG.

  That is, the structure shown in these drawings corresponds to one memory cell included in the magnetic memory illustrated in FIG. That is, it is a 1-bit memory cell of a magnetic memory that operates as a random access memory. This memory cell has a memory element portion 311 and an address selection transistor portion 312.

  The memory element portion 311 includes a magnetoresistive effect element 321 and a pair of wirings 322 and 324 connected thereto. The magnetoresistive effect element 321 is the magnetoresistive effect element according to the embodiment of the present invention as described above with reference to FIGS.

  When reading bit information, a sense current may be supplied to the magnetoresistive effect element 321 to detect a change in resistance.

  On the other hand, the selection transistor portion 312 is provided with a transistor 330 connected via a via 326 and a buried wiring 328. The transistor 330 performs a switching operation according to the voltage applied to the gate 332, and controls opening and closing of the current path between the magnetoresistive effect element 321 and the wiring 334.

  A write wiring 323 is provided below the magnetoresistive element 321 in a direction substantially orthogonal to the wiring 322. These write wirings 322 and 323 can be formed of, for example, aluminum (Al), copper (Cu), tungsten (W), tantalum (Ta), or an alloy containing any of these.

  In the memory cell having such a configuration, when writing bit information to the magnetoresistive element 321, a write pulse current is supplied to the wirings 322 and 323, and a combined magnetic field induced by these currents is applied, thereby applying the magnetoresistive element. The magnetization of the recording layer is appropriately reversed.

  When reading bit information, a sense current is passed through the wiring 322, the magnetoresistive effect element 321 including the magnetic recording layer, and the lower electrode 324, and the resistance value of the magnetoresistive effect element 321 or a change in the resistance value is measured. Is done.

  In the magnetic memory of this example, a stable magnetoresistance change rate can be obtained by using the magnetoresistance effect element as described above with reference to FIGS. As a result, even if the cell size is miniaturized, the magnetic domain of the recording layer can be reliably controlled to ensure reliable writing, and can be reliably read.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, regarding the specific structure of the magnetoresistive effect film and the shape and material of the electrode, bias application film, insulating film, etc., those skilled in the art can implement the present invention in the same manner by appropriately selecting from a known range. The same effect can be obtained.

  For example, when applying a magnetoresistive element to a reproducing magnetic head, the detection resolution of the magnetic head can be defined by providing magnetic shields above and below the element.

  The present invention can be similarly applied not only to the longitudinal magnetic recording system but also to the perpendicular magnetic recording system magnetic head or magnetic reproducing apparatus, and the same effect can be obtained.

  Furthermore, the magnetic reproducing apparatus of the present invention may be a so-called fixed type having a specific recording medium constantly provided, or a so-called “removable” type in which the recording medium can be replaced.

  In addition, all magnetoresistive elements, magnetic heads, magnetic storage / reproduction devices, and magnetics that can be implemented by those skilled in the art based on the magnetic head and magnetic storage / reproduction device described above as embodiments of the present invention. Memory is similarly within the scope of the present invention.

It is a conceptual diagram showing the cross-sectional structure of the magnetoresistive effect element concerning the 1st Embodiment of this invention. It is explanatory drawing which represents notably the mode that the phase-separation layer 9 constricts a sense current. 3 is a conceptual diagram illustrating a specific example of a planar configuration of a phase separation layer 9. FIG. It is a flowchart showing a part of formation process of the phase-separation layer 9 in embodiment of this invention. 3 is a conceptual diagram illustrating a change in a planar structure of a phase separation layer 9. FIG. 3 is a flowchart showing another method for forming the phase separation layer 9. It is a conceptual diagram showing another example in which the oxide of the base material remained. It is a conceptual diagram showing the method of irradiating an ion beam as decomposition | disassembly process S2 which produces spinodal decomposition | disassembly. It is the figure which showed typically the cross-sectional TEM image after spinodal decomposition | disassembly, and the profile of the elemental analysis. It is a schematic diagram which illustrates the cross-section of the phase-separation layer 9 which has a laminated structure. It is a schematic diagram which illustrates the cross-sectional structure of the magnetoresistive effect element concerning embodiment of this invention. It is a schematic diagram which illustrates the cross-sectional structure of the magnetoresistive effect element concerning embodiment of this invention. It is a limited field electron diffraction pattern of a phase separation layer. It is a TEM image of a phase separation layer. It is a limited field electron diffraction pattern of a phase separation layer. It is a HAADF image of a phase separation layer. It is a schematic diagram which illustrates the cross-sectional structure of the magnetoresistive effect element concerning embodiment of this invention. It is a schematic diagram which illustrates the cross-sectional structure of the magnetoresistive effect element concerning embodiment of this invention. It is a schematic diagram which illustrates the cross-sectional structure of the magnetoresistive effect element concerning embodiment of this invention. It is a schematic diagram which illustrates the cross-sectional structure of the magnetoresistive effect element concerning embodiment of this invention. It is a graph showing the relationship between the composition x and the specularity dGs (× 10 ⁻³ : 1 / Ω). It is a schematic cross section showing an example of a BMR type magnetoresistance effect element. It is a principal part perspective view which illustrates schematic structure of the magnetic recording / reproducing apparatus of embodiment of this invention. 5 is an enlarged perspective view of the magnetic head assembly ahead of the actuator arm 155 as viewed from the disk side. FIG. It is a conceptual diagram which illustrates the matrix structure of the magnetic memory of embodiment of this invention. It is a conceptual diagram showing another specific example of the matrix structure of the magnetic memory of embodiment of this invention. It is a conceptual diagram showing principal part sectional structure of the magnetic memory concerning embodiment of this invention. FIG. 22 is a sectional view taken along line A-A ′ of FIG. 21. It is a conceptual diagram which illustrates the schematic cross-section of a spin valve film.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate electrode 2 Underlayer 3 Antiferromagnetic layer 4 Magnetization fixed layer 5, 5A Magnetic coupling interruption layer 5B Interface adjustment phase separation layer 6 Magnetization free layer 7 Protection layer 8 Upper electrode 9 Phase separation layer 10 Intermediate layer 150 Magnetic recording / reproducing apparatus 152 Spindle 153 Head slider 154 Suspension 155 Actuator arm 156 Voice coil motor 157 Spindle 160 Magnetic head assembly 164 Lead wire 200 Magnetic recording medium disk 311 Memory element part 312 Address selection transistor part 312 Selection transistor part 321 Magnetoresistive element 322 Bit Line 322 Line 323 Word line 323 Line 324 Lower electrode 326 Via 328 Line 330 Switching transistor 332 Gate 332 Word line 334 Bit line 334 Word line 350 Column decoder 3 One row decoder 352 sense amplifier 360 decoder

Claims (3)

Between the first ferromagnetic layer whose magnetization direction is substantially fixed in one direction, the second ferromagnetic layer whose magnetization direction changes according to the external magnetic field, and the first and second ferromagnetic layers A magnetoresistive film having an intermediate layer formed on the magnetoresistive film, and a magnetoresistive film electrically connected to the magnetoresistive film that allows a sense current to flow in a direction substantially perpendicular to the film surface of the magnetoresistive film. A method of manufacturing a magnetoresistive effect element having a pair of electrodes,
The solid internal phase separation due to the formation of spinodal decomposition or GP zones, that a layer made of an alloy containing two or more elements gives rise to phase separation to separate the first and second phases in the film plane One selected from the group consisting of oxygen, nitrogen, fluorine, and carbon than the other
A high-resistance phase containing at least one element at a high concentration and having a relatively high resistance;
The first and second phases are low resistance phases having a relatively lower resistance than the one, and
A method of manufacturing a magnetoresistive element, comprising a step of forming a phase separation layer formed between a pair of electrodes . At least one element selected from the group consisting of oxygen, nitrogen, fluorine and carbon,
The preferential reaction is performed with respect to any one of the plurality of phases.
The manufacturing method of the magnetoresistive effect element of description. 3. The method of manufacturing a magnetoresistive effect element according to claim 2, wherein the reaction is performed by forming plasma or radical of the element.