JP2008091551A - Magnetoresistance effect element, magnetic storage device, and magnetic memory device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetoresistance effect element having a high output and a good sensitivity to an external magnetic field, and to provide a magnetic head, magnetic storage device, and magnetic memory device using the same. <P>SOLUTION: A GMR film 30 has such a structure that a base layer 31, antiferromagnetic layer 32, fixed magnetization laminate 33, non-magnetic metal layer 37, diffusion prevention layer 38, free magnetization layer 39, and protection layer 40 are stacked in this order. The free magnetization layer 39 is formed of an Mn-based Heusler alloy, while the diffusion prevention layer 38 is formed of CoFeAl. The composition of the CoFeAl might be set within a region of a ternary-system composition map defined by connecting the points A, B, C, D, E and F in this order, assuming A (55, 10, 35), point B (50, 15, 35), point C (50, 20, 30), point D (55, 25, 20), point E (60, 25, 15) and point F (70, 15, 15) in a coordinates system whose composition is expressed by an arbitrary point (Co content, Fe content, Al content) in the ternary-system composition map. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a magnetoresistive effect element, a magnetic memory device, and a magnetic memory device for reproducing information in a magnetic memory device, and more particularly, to a CPP (flowing sense current in the stacking direction of stacked films constituting the magnetoresistive effect element). The present invention relates to a magnetoresistive effect element having a current-perpendicular-to-plane) type structure.

  In recent years, magnetoresistive elements have been used in magnetic heads of magnetic storage devices as reproducing elements for reproducing information recorded on magnetic recording media. The magnetoresistive effect element reproduces information recorded on the magnetic recording medium using a magnetoresistive effect that converts a change in the direction of the signal magnetic field leaking from the magnetic recording medium into a change in electrical resistance.

  With the increase in recording density of magnetic storage devices, those having a spin valve film have become mainstream. A spin valve film is composed of a fixed magnetic layer whose magnetization is fixed in a predetermined direction, a nonmagnetic layer, and a free magnetic layer whose magnetization direction changes depending on the direction and strength of the leakage magnetic field from the magnetic recording medium. It is configured. The electric resistance value of the spin valve film changes according to the angle formed by the magnetization of the fixed magnetization layer and the magnetization of the free magnetization layer. A change in electrical resistance value is detected as a voltage change by passing a constant sense current through the spin valve film, so that the magnetoresistive element reproduces a bit recorded on the magnetic recording medium.

  Conventionally, the magnetoresistive effect element has adopted a CIP (Current-In-Plane) type structure in which a sense current flows in the in-plane direction of the spin valve film. In order to further increase the recording density of the magnetic recording apparatus, it is necessary to increase the linear recording density and the track density of the magnetic recording medium. On the other hand, in the magnetoresistive effect element, it is necessary to reduce both the element width corresponding to the track width of the magnetic recording medium and the element height (element depth), that is, the element cross-sectional area. In this case, in the CIP type structure, since the current density of the sense current is increased, there is a possibility that performance degradation may occur due to migration of a material constituting the spin valve film due to overheating.

  Therefore, a CPP (Current-Perpendicular-to-Plane) type structure is proposed in which a sense current flows in the stacking direction of the spin valve film, that is, the direction in which the fixed magnetic layer, the nonmagnetic layer, and the free magnetic layer are stacked. Active research is being carried out as a next-generation reproducing element. Since the CPP type spin valve film has a feature that the output hardly changes even when the element width is narrowed, it is suitable for increasing the recording density.

  The output of the CPP type spin valve film is determined by the amount of change in magnetoresistance when an external magnetic field is applied to the spin valve film by sweeping the magnetic field from one direction to the opposite direction. This magnetoresistance change amount is the magnetoresistance change amount of a unit area of the film surface perpendicular to the direction of the sense current. The amount of change in magnetoresistance per unit area is the product of the amount of change in magnetoresistance of the spin valve film and the area of the film surface of the spin valve film. In order to increase the amount of change in magnetoresistance per unit area, it is necessary to use a material having a large product of the spin-dependent bulk scattering coefficient and the specific resistance for the free magnetic layer and the fixed magnetic layer. Spin-dependent bulk scattering refers to the degree to which conduction electrons are scattered in the free magnetic layer or the fixed magnetic layer depending on the spin direction of the conduction electrons. The greater the spin-dependent bulk scattering coefficient, the greater the magnetoresistance change.

As a material having a large spin-dependent bulk scattering coefficient, a magnetoresistive element using a ferromagnetic material having a Heusler alloy composition containing Mn for a free magnetic layer has been proposed (see, for example, Patent Document 1). Furthermore, in Patent Document 1, when a Heusler alloy composition containing Mn is used for a free magnetic layer, Mn atoms diffuse into a nonmagnetic layer of Cu or Cr in contact with the free magnetic layer by heat treatment during manufacture, and the amount of change in magnetoresistance Therefore, a method has been proposed in which a CoFe film is formed between the free magnetic layer and the nonmagnetic layer to avoid a decrease in magnetoresistance change.
JP 2003-218428 A

  However, when a CoFe film is formed between the free magnetic layer and the nonmagnetic layer as in Patent Document 1, the thicker the CoFe film, the more the Mn diffusion to the nonmagnetic layer side can be suppressed. Magnetic force also increases. For this reason, the magnetization of the free magnetic layer and the CoFe film is less sensitive to an external magnetic field.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a magnetoresistive effect element for sensitivity to detect an external magnetic field at a high output by suppressing diffusion of Mn, and a magnetic memory using the same. An apparatus and a magnetic memory device are provided.

  According to one aspect of the present invention, there is provided a CPP-type magnetoresistive element, in which a fixed magnetic layer, a nonmagnetic metal layer, a diffusion prevention layer, and a free magnetic layer are stacked in this order, and the free magnetic layer Is made of a Mn-based Heusler alloy, and the diffusion preventing layer is made of CoFeAl.

  According to the present invention, a diffusion prevention layer made of CoFeAl is provided between the free magnetic layer and the nonmagnetic metal layer to prevent Mn atoms of the Mn-based Heusler alloy of the free magnetic layer from diffusing into the nonmagnetic metal layer. To do. In addition, since the CoFeAl film has a lower saturation magnetic flux density than CoFe, when the magnetization amount represented by film thickness × saturation magnetic flux density is set to a predetermined value, the film thickness of the free magnetic layer can be increased more than CoFe, and free magnetization This is because the Mn-based Heusler alloy in the layer has higher spin-dependent bulk scattering than CoFe. Therefore, a high-output magnetoresistive element can be obtained. At the same time, since the diffusion preventing layer made of CoFeAl is provided in contact with the free magnetic layer, the magnetization of the diffusion preventing layer and the magnetization of the free magnetic layer respond to an external magnetic field while being exchange coupled. Since CoFeAl has a lower coercive force and a lower saturation magnetic flux density than CoFe, the magnetization of the laminate of the diffusion prevention layer and the free magnetic layer improves the sensitivity to an external magnetic field. As a result, a magnetoresistive element having high output and good sensitivity to an external magnetic field can be obtained.

  According to another aspect of the present invention, there is provided a CPP type magnetoresistive element, wherein a fixed magnetic layer, a nonmagnetic insulating layer, a free magnetic layer, another diffusion prevention layer, and a protective layer are arranged in this order. A magnetoresistive effect element is provided, wherein the protective layer is made of a nonmagnetic metal material, the free magnetic layer is made of a Mn-based Heusler alloy, and the other diffusion prevention layer is made of CoFeAl.

  According to the present invention, a diffusion preventing layer made of CoFeAl is provided between the free magnetic layer and the protective film, and Mn atoms of the Mn-based Heusler alloy of the free magnetic layer are prevented from diffusing into the protective film. In addition, since the CoFeAl film has a lower saturation magnetic flux density than CoFe, when the magnetization amount represented by film thickness × saturation magnetic flux density is set to a predetermined value, the film thickness of the free magnetic layer can be increased more than CoFe, and free magnetization This is because the Mn-based Heusler alloy in the layer has higher spin-dependent bulk scattering than CoFe. Therefore, a high-output magnetoresistive element can be obtained. Since the other anti-diffusion layer is provided in contact with the free magnetic layer, the magnetization of the other anti-diffusion layer and the magnetization of the free magnetic layer respond to an external magnetic field while being exchange-coupled with each other. Since CoFeAl of the other anti-diffusion layer has a lower coercive force and a lower saturation magnetic flux density than CoFe, the magnetization of the laminate of the other anti-diffusion layer and the free magnetic layer improves the sensitivity to the external magnetic field. As a result, a magnetoresistive element having high output and good sensitivity to an external magnetic field can be obtained.

  According to another aspect of the present invention, there is provided a magnetic storage device including a magnetic head having the magnetoresistive effect element according to any one of the above, a recording element, and a magnetic recording medium.

  According to the present invention, since the magnetoresistive element has a high output and a high sensitivity to a signal magnetic field from a magnetic recording medium, it is possible to increase the recording density of the magnetic storage device.

  According to another aspect of the present invention, a CPP type magnetoresistive film in which a fixed magnetic layer, a nonmagnetic metal layer, a diffusion prevention layer, and a free magnetic layer are stacked, and the magnetoresistive film A writing means for applying a magnetic field to direct the magnetization of the free magnetic layer in a predetermined direction; and a reading means for detecting a resistance value by supplying a sense current to the magnetoresistive film; A magnetic memory device is provided in which is made of a Mn-based Heusler alloy and the diffusion prevention layer is made of CoFeAl.

  According to the present invention, since the magnetoresistive film has a high output, the difference between the magnetoresistive values corresponding to “0” and “1” held at the time of reading information is large. it can. Further, according to the present invention, a diffusion preventing layer for preventing diffusion of Mn contained in the free magnetic layer into the nonmagnetic metal layer is provided between the nonmagnetic metal layer and the free magnetic layer. The diffusion preventing layer can suppress the diffusion of Mn into the nonmagnetic metal layer due to a temperature increase such as heat treatment in the manufacturing process of the magnetic memory device or heat generation during use. As a result, the heat resistance is excellent, and the deterioration of the magnetoresistance change amount can be suppressed.

  According to the present invention, it is possible to realize a magnetoresistive effect element having high output and good sensitivity to a magnetic field, a magnetic storage device using the same, and a magnetic memory device.

  Embodiments will be described below with reference to the drawings. For convenience of explanation, unless otherwise specified, “magnetic resistance change amount ΔRA of unit area” is abbreviated as “magnetic resistance change amount ΔRA” or simply “ΔRA”.

(First embodiment)
A composite magnetic head including a magnetoresistive effect element according to a first embodiment of the present invention and an inductive recording element will be described.

  FIG. 1 is a diagram showing the main part of the medium facing surface of a composite magnetic head. In FIG. 1, the direction of arrow X indicates the moving direction of a magnetic recording medium (not shown) facing the magnetoresistive element.

Referring to FIG. 1, a magnetic head 10 is roughly composed of a magnetoresistive element 20 formed on a flat ceramic substrate 11 such as Al ₂ O ₃ —TiC, which is a base of a head slider, The inductive recording element 13 is formed.

The inductive recording element 13 includes an upper magnetic pole 14 having a width corresponding to the track width of the magnetic recording medium on the medium facing surface, and a lower magnetic pole 16 facing the upper magnetic pole 14 with a recording gap layer 15 made of a nonmagnetic material interposed therebetween. A yoke (not shown) that magnetically connects the upper magnetic pole 14 and the lower magnetic pole 16, a coil (not shown) that winds the yoke and induces a recording magnetic field by a recording current, and the like. The upper magnetic pole 14, the lower magnetic pole 16, and the yoke are made of a soft magnetic material. Examples of the soft magnetic material include materials having a high saturation magnetic flux density in order to secure a recording magnetic field, such as Ni ₈₀ Fe ₂₀ , CoZrNb, FeN, FeSiN, FeCo, and CoNiFe. The inductive recording element 13 is not limited to this, and an inductive recording element having a known structure can be used.

  The magnetoresistive effect element 20 includes a lower electrode 21, a magnetoresistive effect film 30 (hereinafter referred to as “GMR film 30”), an alumina film 25, an upper electrode on an alumina film 12 formed on the surface of the ceramic substrate 11. 22 is laminated. The GMR film 30 is electrically connected to the lower electrode 21 and the upper electrode 22, respectively.

  A magnetic domain control film 24 is provided on both sides of the GMR film 30 via an insulating film 23. The magnetic domain control film 24 is made of, for example, a laminate of a Cr film and a ferromagnetic CoCrPt film. The magnetic domain control film 24 makes the free magnetic layer (reference numeral 39 shown in FIG. 2) constituting the GMR film 30 a single magnetic domain and prevents the occurrence of Barkhausen noise.

  The lower electrode 21 and the upper electrode 22 have a function as a magnetic shield in addition to a function as a flow path of the sense current Is. Therefore, the lower electrode 21 and the upper electrode 22 are made of a soft magnetic alloy such as NiFe or CoFe. Further, a conductive film, such as a Cu film, a Ta film, or a Ti film, may be provided at the interface between the lower electrode 21 and the GMR film 30. These conductive films improve the crystallinity of each layer constituting the GMR film 30.

  The magnetoresistive effect element 20 and the inductive recording element 13 are covered with an alumina film, a hydrogenated carbon film, or the like in order to prevent corrosion or the like.

  The sense current Is flows, for example, from the upper electrode 22 through the GMR film 30 in a direction substantially perpendicular to the film surface (in the direction of lamination of the GMR film and reaches the lower electrode 21. The GMR film 30 leaks from the magnetic recording medium. The electric resistance value, so-called magnetoresistance value, changes in accordance with the intensity and direction of the magnetic field, and the magnetoresistive effect element 20 causes the change in the magnetoresistance value of the GMR film 30 to flow a sense current Is of a predetermined current amount. In this way, the magnetoresistive element 20 reproduces information recorded on the magnetic recording medium, and the direction in which the sense current Is flows is not limited to the direction shown in FIG. The magnetic recording medium may be moved in the opposite direction.

  The recording element 13 and the magnetoresistive element 20 of the magnetic head 10 are formed by known methods such as sputtering, vacuum deposition, chemical vapor deposition, photolithography, and dry etching. Patterning methods combining methods can be used.

  Also, the composite magnetic head 10 is shown as one embodiment of the present invention. However, as another embodiment of the present invention, the magnetic head is a magnetoresistive effect element according to the first embodiment (or later). A read-only magnetic head including only the magnetoresistive effect element according to the second embodiment to be described may be used.

  Next, five examples (first to fifth examples) of the GMR film 30 constituting the magnetoresistive element 20 will be described. Any of the GMR films of the first to fifth examples may be applied to the magnetoresistive effect element 20.

[GMR film of first example]
FIG. 2 is a cross-sectional view of a first example GMR film constituting the magnetoresistive effect element according to the first embodiment.

  Referring to FIG. 2, the GMR film 30 of the first example includes an underlayer 31, an antiferromagnetic layer 32, a fixed magnetization stack 33, a nonmagnetic metal layer 37, a diffusion prevention layer 38, a free magnetization layer 39, and a protective layer. 40 is formed by sequentially laminating. The GMR film 30 has a so-called single spin valve structure.

  The underlayer 31 is formed on the surface of the lower electrode 21 shown in FIG. The underlayer 31 is composed of, for example, a NiCr film, a laminate of a Ta film (for example, a film thickness of 5 nm) and a NiFe film (for example, a film thickness of 5 nm), or the like. The NiFe film preferably has a Fe content in the range of 17 atomic% to 25 atomic%. By using the NiFe film having such a composition, the antiferromagnetic layer 32 is epitaxially grown on the surface of the (111) crystal plane which is the crystal growth direction of the NiFe film and the crystallographically equivalent crystal plane. As a result, the crystallinity of the antiferromagnetic layer 32 can be improved, and further, the crystallinity of the free magnetic layer 39 is improved through the layers 34 to 38 stacked on the antiferromagnetic layer 32. The coercive force of the magnetic layer 39 can be reduced.

  The antiferromagnetic layer 32 is made of, for example, a Mn-TM alloy having a film thickness of 4 nm to 30 nm (preferably 4 nm to 10 nm) (TM is selected from at least one of Pt, Pd, Ni, Ir, and Rh). Composed. Examples of the Mn-TM alloy include PtMn, PdMn, NiMn, IrMn, and PtPdMn. The antiferromagnetic layer 32 exerts an exchange interaction on the first pinned magnetization layer 34 of the pinned magnetization stack 33 to pin the magnetization of the first pinned magnetization layer 34 in a predetermined direction.

  The fixed magnetization stack 33 is formed by sequentially stacking a first fixed magnetization layer 34, a nonmagnetic coupling layer 35, and a second fixed magnetization layer 36 from the antiferromagnetic layer 32 side. The fixed magnetization stack 33 has a so-called stacked ferrimagnetic structure in which the magnetization of the first fixed magnetization layer 34 and the magnetization of the second fixed magnetization layer 36 are antiferromagnetically exchange-coupled and the magnetization directions are antiparallel to each other. Have.

  The first and second pinned magnetic layers 34 and 36 are each made of a ferromagnetic material containing at least one of Co, Ni, and Fe having a thickness of 1 to 30 nm. Examples of the ferromagnetic material include CoFe, CoFeB, CoFeAl, NiFe, FeCoCu, and CoNiFe.

As the second pinned magnetic layer 36, CoFeZ (where Z is at least one element selected from Al, Si, Ga, Ge, Cu, Mg, V, Cr, In, Sn, B, and Ni). )), And a ferromagnetic material that forms a Heusler alloy crystal structure with a composition of Co ₅₀ Fe ₂₅ Z ₂₅ (however, the content is expressed in atomic%) may be used. Since the CoFeZ ferromagnetic material has a large spin-dependent bulk scattering coefficient, ΔRA of the magnetoresistive element can be increased. Since the ferromagnetic material of the second pinned magnetic layer 36 does not adversely affect the characteristics of the magnetoresistive element even if the coercive force is high, it can be selected from a composition range having a large spin-dependent bulk scattering coefficient.

  Further, examples of the ferromagnetic material suitable for the first pinned magnetic layer 34 include CoFe and NiFe in terms of low specific resistance. This is because the magnetization of the first pinned magnetic layer 34 is opposite to the magnetization direction of the second pinned magnetic layer 36, and therefore, when the sign of the spin-dependent bulk scattering coefficient is the same as that of the second pinned magnetic layer 36. The first pinned magnetic layer 34 acts in a direction to reduce the magnetoresistance change ΔRA. In such a case, the use of a ferromagnetic material having a low specific resistance can suppress a decrease in the magnetoresistance change ΔRA.

  The thickness of the nonmagnetic coupling layer 35 is set in a range where the first pinned magnetic layer 34 and the second pinned magnetic layer 36 are antiferromagnetically exchange coupled. The range is 0.4 nm to 1.5 nm (preferably 0.4 nm to 0.9 nm). The nonmagnetic coupling layer 35 is made of a nonmagnetic material such as Ru, Rh, Ir, Ru-based alloy, Rh-based alloy, or Ir-based alloy. As the Ru alloy, any one of Co, Cr, Fe, Ni, and Mn, or a nonmagnetic material with these alloys is suitable for Ru.

  Each of the first and second pinned magnetic layers 34 and 36 may be not only one layer but also a stacked body of two or more layers, each of which is a combination of the same elements. Materials having different composition ratios may be used, or materials combining different elements may be used.

  Further, although not shown, a ferromagnetic junction layer made of a ferromagnetic material having a saturation magnetic flux density higher than that of the first pinned magnetization layer 34 may be provided between the first pinned magnetization layer 34 and the antiferromagnetic layer 32. Good. As a result, the exchange interaction acting between the first pinned magnetic layer 34 and the antiferromagnetic layer 32 can be increased, and the magnetization direction of the first pinned magnetic layer 34 is displaced or reversed from a predetermined direction. Can be avoided.

  The nonmagnetic metal layer 37 is made of a nonmagnetic metal material having a film thickness of 1.5 nm to 10 nm, for example. Suitable conductive materials for the nonmagnetic metal layer 37 include Cu, Al, Cr and the like.

  The diffusion preventing layer 38 is made of CoFeAl. By using CoFeAl, as described below, it is possible to increase the output and the sensitivity of the magnetoresistive element.

  As will be described later with reference to FIG. 7, CoFeAl suppresses diffusion of Mn of the Mn-based Heusler alloy of the free magnetic layer 39 into the nonmagnetic metal layer 37. Therefore, it is possible to suppress a decrease in the magnetoresistance change ΔRA due to Mn diffusion. In particular, when the nonmagnetic metal layer 37 is Cu, Mn is easily diffused and the magnetoresistance change ΔRA is extremely reduced. Therefore, the diffusion preventing layer 38 avoids the reduction.

  Furthermore, as will be described later with reference to FIG. 8, CoFeAl has lower coercive force and saturation magnetic flux density than CoFe. The coercive force indicates the difficulty of magnetization saturation, and the lower the coercive force, the better the response to an external magnetic field. Since CoFeAl has a lower coercive force than CoFe, the direction of magnetization is reversed by a lower external magnetic field, and can react to the external magnetic field together with the free magnetic layer 39.

  In addition, when the free magnetization layer 39 and the diffusion prevention layer 38 follow the external magnetic field and the magnetization rotates, the ease of rotation of magnetization depends on the saturation magnetic flux density and the film thickness of each of the free magnetization layer 39 and the diffusion prevention layer 38. (Hereinafter referred to as “saturation magnetic flux density film thickness product”), and the sum is set to a predetermined value or less. Since CoFeAl has a lower saturation magnetic flux density than CoFe, and the thickness of the Mn diffusion preventing layer is considered to be substantially the same as CoFe, the saturation magnetic flux density film area product can be suppressed more than CoFe. Therefore, the suppressed saturation magnetic flux density film thickness product can be allocated to the free magnetic layer 39, so that the film thickness of the free magnetic layer 39 can be increased. Since the spin-dependent bulk scattering coefficient of the Mn-based Heusler alloy of the free magnetic layer 39 is larger than that of CoFe or CoFeAl, the magnetoresistance change ΔRA can be increased by increasing the film thickness of the free magnetic layer 39, and the magnetoresistive element 20 output can be increased.

Further, the spin-dependent bulk scattering coefficient of CoFeAl is approximately the same as the spin-dependent bulk scattering coefficient of CoFe, which is a soft magnetic material, and has a relatively larger spin-dependent bulk scattering coefficient than other soft magnetic materials. For example, the spin-dependent bulk scattering coefficient of Co ₉₀ Fe ₁₀ is 0.55, whereas the spin-dependent bulk scattering coefficient of Co ₅₀ Fe ₂₀ Al ₃₀ is 0.50. The specific resistance of CoFeAl is much larger than that of CoFe. For example, Co ₉₀ Fe ₁₀ is ₂₀ μΩcm, whereas Co ₅₀ Fe ₂₀ Al ₃₀ is 130 μΩcm, which is about six times that of Co ₉₀ Fe ₁₀ . Since the magnetoresistance change depends on the product of the spin-dependent bulk scattering coefficient and the specific resistance, CoFeAl has a much larger magnetoresistance change ΔRA than CoFe. Therefore, by using CoFeAl for the diffusion preventing layer 38, the magnetoresistance change ΔRA can be significantly increased, and the output of the magnetoresistive effect element 20 can be further increased.

  Furthermore, since the spin-dependent bulk scattering coefficient and specific resistance of CoFeAl are less dependent on the composition ratio of CoFeAl, there is also an advantage that the composition management of CoFeAl during manufacture becomes easy. CoFeAl is also preferably used for the free magnetic layer 38 described below because of these advantages.

Further, the CoFeAl of the diffusion preventing layer 38 can further reduce the coercive force by selecting the composition as shown in FIGS. 9 and 10 later. That is, as shown in FIG. 10, in the ternary composition diagram of CoFeAl, when the coordinates of each composition are represented as (Co content, Fe content, Al content), point A (55, 10, 35), As point B (50, 15, 35), point C (50, 20, 30), point D (55, 25, 20), point E (60, 25, 15), point F (70, 15, 15) , Point A, point B, point C, point D, point E, point F, and point A are set in a composition within the range ABCDEFA in which the respective points are connected by straight lines in this order (indicated by a thick solid line in FIG. 10). range). This composition range has a magnetoresistance change ΔRA equivalent to Co ₅₀ Fe ₂₅ Al ₂₅ , which is a Heusler alloy composition, and has a reduced coercive force. Therefore, the magnetoresistive effect element 20 can obtain a high output and can increase the sensitivity to the signal magnetic field.

  Furthermore, when the composition range of the free magnetic layer 38 is expressed as (Co content, Fe content, Al content) in the CoFeAl ternary composition diagram shown in FIG. A (55, 10, 35), point B (50, 15, 35), point C (50, 20, 30), point G (65, 20, 15), point A, point B, point C, point G and point A are set to the compositions in the regions connected in a straight line in this order, respectively (in the range indicated by the thick broken line in FIG. 10), so that the coercive force of the diffusion preventing layer 38 itself can be reduced to 20 Oe or less. The sensitivity to the signal magnetic field can be further increased.

  Moreover, it is preferable that the diffusion prevention layer 38 is set in a film thickness range of 0.5 nm to 2.0 nm. When the thickness of the diffusion prevention layer 38 is less than 0.5 nm, the Mn diffusion prevention function is reduced. When the thickness exceeds 2.0 nm, the thickness of the GMR film is increased, the read gap length is increased, and the recording density is increased. Playback output cannot be obtained sufficiently.

  The free magnetic layer 39 is made of a Mn-based Heusler alloy. Heusler alloys have a spin-dependent bulk scattering coefficient comparable to that of CoFe, and have a much higher specific resistance than CoFe. For this reason, the magnetoresistance change ΔRA is much larger than when CoFe is used.

In the case of a Mn-based Heusler alloy, such as Co ₂ MnGe, the crystal structure has Co at the apex of the body-centered cubic lattice, and Mn and Ge are alternately arranged regularly at the center. By adopting such a structure, one electron spin (for example, up spin) has a metallic band structure, and the other electron spin (for example, down spin) has a material called a half metal having an insulating band structure. . As a result, the spin bulk scattering coefficient, that is, the proportion of spin scattering in the magnetic material increases, and the magnetoresistance change ΔRA increases.

As the Mn-based Heusler alloy suitable for the free magnetic layer 39, Co ₂ MnX (X is one of the group consisting of Al, Ge, Si, Ga, In, Sb, and Sn), Ni ₂ MnAl, Ni ₂ MnSn, Cu ₂ MnAl, Pd ₂ MnIn, Pd ₂ MnSn, Pd ₂ MnSb, NiMnSb, PtMnSb, PdMnSb, and PtMnSn.

  The free magnetic layer 39 preferably has a film thickness of, for example, 2 nm to 8 nm, and preferably has a saturation magnetic flux density film thickness product of 8 nm T or less in combination with the diffusion prevention layer. However, the saturation magnetic flux density film thickness product should be set to 2 nmT or more in view of obtaining a sufficient reproduction output.

  The protective layer 40 is made of a nonmagnetic metal material, and is made of, for example, a metal film containing any one of Ru, Cu, Ta, Au, Al, and W, and may be made of a laminate of these metal films. . The protective layer 40 can prevent the free magnetic layer 39 from being oxidized during a heat treatment or the like for causing antiferromagnetism of the antiferromagnetic layer 32 described below to appear.

  Although not shown, as a modification of the GMR film 30 of the first example, the same material and film thickness range as the diffusion prevention layer 38 are selected between the free magnetic layer 39 and the protective layer 40. It is preferable to further provide another diffusion preventing layer. Depending on the material of the protective layer 40 (for example, Cu), Mn in the free magnetic layer 39 may diffuse into the protective layer 40. As a result, the magnetic moment of the free magnetic layer 39 decreases, and the magnetoresistance change ΔRA decreases. By providing another diffusion preventing layer, the diffusion of Mn can be prevented and the deterioration of ΔRA can be avoided.

  Next, a method for forming the GMR film 30 of the first example will be described with reference to FIG. First, each of the underlayer 31, the antiferromagnetic layer 32, the fixed magnetization stack 33, the nonmagnetic metal layer 37, the diffusion prevention layer 38, and the free magnetization layer 39 is formed by sputtering, vapor deposition, CVD, or the like. Layers are sequentially formed using the materials described above.

  Next, the laminated body thus obtained is heat-treated while applying a magnetic field in a predetermined direction. The heat treatment is performed in a vacuum atmosphere, for example, a heating temperature of 250 ° C. to 320 ° C., a heating time of about 2 to 4 hours, and an applied magnetic field of 1592 kA / m. By this heat treatment, the magnetization direction of the antiferromagnetic layer 32 is set to a predetermined direction, and the magnetization of the fixed magnetic layer 33 is fixed in a predetermined direction by the exchange interaction between the antiferromagnetic layer 32 and the fixed magnetic layer 33. can do. In this heat treatment, some materials of the Mn-TM alloy described above are ordered and antiferromagnetism appears.

  As explained above, the GMR film 30 of the first example is provided with the diffusion prevention layer 38 made of CoFeAl between the free magnetic layer 39 and the nonmagnetic metal layer 37, so that the Mn-based Heusler alloy of the free magnetic layer 39 is made of. Mn atoms are prevented from diffusing into the nonmagnetic metal layer 37. Further, since the CoFeAl film has a lower saturation magnetic flux density than CoFe, the film thickness of the free magnetic layer 39 can be increased, and the Mn-Heusler alloy of the free magnetic layer 39 has a spin-dependent bulk scattering larger than that of CoFe. Therefore, a high-output magnetoresistive element can be obtained.

  At the same time, in the GMR film 30 of the first example, since the diffusion preventing layer 38 is provided in contact with the free magnetic layer 39, the magnetization of the diffusion preventing layer 38 and the magnetization of the free magnetic layer 39 are exchange-coupled to each other while being externally coupled. Responds to magnetic fields. Since CoFeAl of the diffusion prevention layer 38 has a lower coercive force and a lower saturation magnetic flux density than CoFe, the magnetization of the laminated body of the diffusion prevention layer 38 and the free magnetic layer 39 is improved in sensitivity to an external magnetic field. As a result, a magnetoresistive element having high output and good sensitivity to an external magnetic field can be obtained.

[GMR film of second example]
Next, a second example GMR film constituting the magnetoresistive effect element according to the first embodiment will be described. The GMR film of the second example is a modification of the GMR film 30 of the first example shown in FIG.

  FIG. 3 is a cross-sectional view of a second example GMR film constituting the magnetoresistive effect element according to the first embodiment. In the figure, portions corresponding to the portions described above are denoted by the same reference numerals, and description thereof is omitted.

  Referring to FIG. 3, the GMR film 50 of the second example includes an underlayer 31, an antiferromagnetic layer 32, a fixed magnetization stack 53, a second diffusion prevention layer 51, a nonmagnetic metal layer 37, and a first diffusion prevention layer. 38, a free magnetic layer 39, and a protective layer 40 are sequentially stacked. The fixed magnetization stack 53 is formed by sequentially stacking a first fixed magnetization layer 34, a nonmagnetic coupling layer 35, and a second fixed magnetization layer 56 from the antiferromagnetic layer 32 side. The GMR film 50 has a single spin valve structure. The first diffusion preventing layer 38 has the same material and film thickness as the diffusion preventing layer 38 in FIG.

  In the GMR film 50, the second pinned magnetic layer 56 is made of the same Mn-based Heusler alloy as the material of the free magnetic layer 39. The second pinned magnetic layer 56 is preferably selected from the suitable Mn-based Heusler alloys described in the first example GMR film. The second pinned magnetic layer 56 may be made of the same material as the free magnetic layer 39 or may be made of a different material. By using a Mn-based Heusler alloy for the second pinned magnetization layer 56, the magnetoresistance change ΔRA can be further improved as compared with the GMR film of the first example, and the output of the magnetoresistive effect element 10 can be further increased.

  The second diffusion prevention layer 51 is made of CoFeAl. By using CoFeAl, diffusion of Mn of the Mn-based Heusler alloy of the second pinned magnetic layer 56 into the nonmagnetic metal layer 37 is suppressed. Therefore, it is possible to suppress a decrease in the magnetoresistance change ΔRA due to Mn diffusion. In particular, when the nonmagnetic metal layer 37 is Cu, Mn is easily diffused and the magnetoresistance change ΔRA is extremely reduced. Therefore, the second diffusion prevention layer 51 avoids the reduction.

  As described above, the GMR film 50 of the second example is provided with the second diffusion preventing layer 51 that prevents the Mn atoms from diffusing into the nonmagnetic metal layer 37 in which the second pinned magnetic layer 56 is made of a Mn-based Heusler alloy. It has been. Therefore, it is possible to realize a magnetoresistive effect element with higher output and good sensitivity to a signal magnetic field.

  Although not shown, as a modification of the GMR film 50 of the second example, the same as the second diffusion prevention layer 51 is provided between the nonmagnetic coupling layer 35 and the second pinned magnetization layer 56 shown in FIG. A CoFeAl film selected from the composition and film thickness range may be formed. As a result, the magnetization of the second pinned magnetic layer 56 is antiferromagnetically coupled to the magnetization of the first pinned magnetic layer 34 via the CoFeAl film by a stronger exchange interaction, and the magnetization of the entire pinned magnetic stack 53 is not desired. Can avoid inversion.

  The method for forming the GMR film 50 according to the second example and the GMR film according to the modification are substantially the same as those of the GMR film according to the first example, and the description thereof will be omitted. The same is omitted in the following examples.

[GMR film of third example]
Next, a third example GMR film constituting the magnetoresistive effect element according to the first embodiment will be described. The third example GMR film is a modification of the first example GMR film 30 shown in FIG.

  FIG. 4 is a cross-sectional view of a third example GMR film constituting the magnetoresistive effect element according to the first embodiment. In the figure, portions corresponding to the portions described above are denoted by the same reference numerals, and description thereof is omitted.

  Referring to FIG. 4, the GMR film 60 of the third example includes an underlayer 31, a lower antiferromagnetic layer 32, a lower fixed magnetization stack 33, a lower nonmagnetic metal layer 37, a lower diffusion prevention layer 38, a free magnetization layer. 39, an upper diffusion prevention layer 68, an upper nonmagnetic metal layer 67, an upper fixed magnetization stack 63, an upper antiferromagnetic layer 62, and a protective layer 40 are sequentially stacked. That is, the GMR film 60 includes an upper diffusion prevention layer 68, an upper nonmagnetic metal layer 67, and an upper fixed magnetization stack between the free magnetic layer 39 and the protective layer 40 of the GMR film 30 of the first example shown in FIG. 63, and an upper antiferromagnetic layer 62 is provided. The GMR film 60 has a so-called dual spin valve structure. The lower antiferromagnetic layer 32, the lower fixed magnetization stack 33, the lower nonmagnetic metal layer 37, and the lower diffusion prevention layer 38 are each an antiferromagnetic layer of the GMR film 30 of the first example shown in FIG. 32, the fixed magnetic layer 33, the nonmagnetic metal layer 37, and the diffusion preventing layer 38 have the same material and film thickness, so the same reference numerals are used.

  The upper diffusion prevention layer 68, the upper nonmagnetic metal layer 67, and the upper antiferromagnetic layer 62 are made of the same material as the lower diffusion prevention layer 38, the lower nonmagnetic metal layer 37, and the lower antiferromagnetic layer 32, respectively. And the film thickness is set in the same range.

  The upper pinned magnetization stack 63 is formed by sequentially stacking an upper second pinned magnetization layer 66, an upper nonmagnetic coupling layer 65, and an upper first pinned magnetization layer 64 from the upper nonmagnetic metal layer 67 side. Has a ferri structure. The upper first pinned magnetization layer 64, the upper nonmagnetic coupling layer 65, and the upper second pinned magnetization layer 66 are the lower first pinned magnetization layer 34, the lower nonmagnetic coupling layer 35, and the lower second pinned magnetization layer 36, respectively. The same material can be used, and the film thickness is also set in the same range.

  In the GMR film 60, the free magnetic layer 39 is made of the same Mn-based Heusler alloy as the free magnetic layer 39 of the GMR film 30 of the first example shown in FIG. A lower diffusion prevention layer 38 and an upper diffusion prevention layer 68 made of CoFeAl are formed between the nonmagnetic metal layer 67 and each other. Accordingly, Mn atoms of the Mn-based Heusler alloy of the free magnetic layer 39 are prevented from diffusing into the lower nonmagnetic metal layer 37 and the upper nonmagnetic metal layer 67. In addition, the spin-dependent bulk scattering of the Mn-based Heusler alloy is larger than that of CoFe, and the CoFeAl film has a lower saturation magnetic flux density than that of CoFe. Therefore, the thickness of the free magnetic layer 39 can be increased. Therefore, a high-output magnetoresistive element can be obtained.

  At the same time, since the lower diffusion prevention layer 38 and the upper diffusion prevention layer 68 are provided in contact with the free magnetic layer 39, the magnetization of the lower diffusion prevention layer 38 and the upper diffusion prevention layer 68 and the magnetization of the free magnetic layer 39 are Responds to an external magnetic field while being exchange coupled to each other. Since CoFeAl of the lower diffusion prevention layer 38 and the upper diffusion prevention layer 68 has a lower coercive force and a lower saturation magnetic flux density than CoFe, the magnetizations of the lower diffusion prevention layer 38, the upper diffusion prevention layer 68, and the free magnetic layer 39 are sensitive to an external magnetic field. Will improve. As a result, a magnetoresistive element having high output and good sensitivity to an external magnetic field can be obtained.

  Further, the GMR film 60 includes a spin valve structure including a lower fixed magnetization stack 33, a lower nonmagnetic metal layer 37, a lower diffusion prevention layer 38, and a free magnetization layer 39, a free magnetization layer 39, an upper diffusion prevention layer 68, The spin valve structure including the upper nonmagnetic metal layer 67 and the upper fixed magnetization stack 63 is also included. Therefore, the magnetoresistance change ΔRA of the GMR film 60 increases and is approximately twice the magnetoresistance change ΔRA of the GMR film of the first example. As a result, the magnetoresistive effect element including the GMR film 60 of the third example can realize a higher output magnetoresistive effect element than the case of including the GMR film of the first example. The method for forming the GMR film 60 is substantially the same as the method for forming the GMR film of the first example, and a description thereof will be omitted.

  As described above, the GMR film 60 of the third example has the same effect as that of the GMR film of the first example, and the magnetoresistance change amount approximately twice the magnetoresistance change ΔRA of the GMR film of the first example. It has ΔRA. As a result, an even higher output magnetoresistive element can be realized.

[GMR film of fourth example]
Next, a fourth example GMR film constituting the magnetoresistive effect element according to the first embodiment will be described. The fourth example GMR film is a modification of the third example GMR film 60 shown in FIG.

  FIG. 5 is a cross-sectional view of a fourth example GMR film constituting the magnetoresistive effect element according to the first embodiment. In the figure, portions corresponding to the portions described above are denoted by the same reference numerals, and description thereof is omitted.

  Referring to FIG. 5, the GMR film 70 of the fourth example includes an underlayer 31, a lower antiferromagnetic layer 32, a lower fixed magnetization stack 71, a lower nonmagnetic metal layer 37, a lower second diffusion prevention layer 38, a free layer. The magnetic layer 39, the upper first diffusion prevention layer 68, the upper nonmagnetic metal layer 67, the upper fixed magnetization stack 72, the upper antiferromagnetic layer 62, and the protective layer 40 are sequentially stacked. The lower pinned magnetization stack 71 has a lower first pinned magnetization layer 34, a lower nonmagnetic coupling layer 35, a lower second pinned magnetization layer 56, and a lower second diffusion prevention layer 73 stacked in this order from the lower antiferromagnetic layer 32 side. It becomes. In addition, the upper fixed magnetization stack 72 includes an upper second diffusion prevention layer 74, an upper second fixed magnetization layer 76, an upper nonmagnetic coupling layer 65, and an upper first fixed magnetization layer 64 from the upper nonmagnetic metal layer 67 side. They are laminated in order.

  In the GMR film 70, the lower second pinned magnetic layer 56 and the upper second pinned magnetic layer 76 are made of the same Mn-based Heusler alloy as the material of the free magnetic layer 39. The second pinned magnetic layer 56 is preferably selected from the suitable Mn-based Heusler alloys described in the first example GMR film. The lower second pinned magnetic layer 56 and the upper second pinned magnetic layer 76 may be made of the same material as the free magnetic layer 39 or different materials. By using a Mn-based Heusler alloy for the lower second pinned magnetic layer 56 and the upper second pinned magnetic layer 76, the magnetoresistance change ΔRA can be further improved as compared with the GMR film of the third example. Higher output can be achieved.

  Further, in the GMR film 70, a lower second diffusion prevention layer 73 is provided between the lower second fixed magnetic layer 56 and the lower nonmagnetic metal layer 37, and the upper nonmagnetic metal layer 67 and the upper second fixed magnetic layer 76. An upper second diffusion preventing layer 74 is provided between the first and second diffusion preventing layers 74. The lower second diffusion prevention layer 73 and the upper second diffusion prevention layer 74 are made of CoFeAl. By using CoFeAl, diffusion of Mn of the Mn-based Heusler alloy of the lower second fixed magnetization layer 56 and the upper second diffusion prevention layer 74 to the lower nonmagnetic metal layer 37 and the upper nonmagnetic metal layer 67 is suppressed. Therefore, it is possible to suppress a decrease in the magnetoresistance change ΔRA due to Mn diffusion. In particular, when the nonmagnetic metal layer 37 is Cu, Mn is easily diffused and the magnetoresistance change ΔRA is extremely reduced. Therefore, the lower second diffusion prevention layer 73 and the upper second diffusion prevention layer 74 avoid the reduction.

As described above, the GMR film 70 of the fourth example has the same effect as the GMR film of the third example, and further, the effect of the Mn-based Heusler alloy of the lower second fixed magnetic layer 56 and the upper second fixed magnetic layer 76, Further, the magnetoresistance change ΔRA can be increased by the Mn diffusion inhibiting effect of the lower second diffusion prevention layer 73 and the upper second diffusion prevention layer 74, and the output can be further increased.

[GMR film of fifth example]
Next, a fifth example GMR film constituting the magnetoresistive effect element according to the first embodiment will be described. The fifth example GMR film is a modification of the fourth example GMR film 70 shown in FIG.

  FIG. 6 is a cross-sectional view of a fifth example GMR film constituting the magnetoresistance effect element according to the first exemplary embodiment. In the figure, portions corresponding to the portions described above are denoted by the same reference numerals, and description thereof is omitted.

  Referring to FIG. 6, the GMR film 80 of the fifth example includes an underlayer 31, a lower antiferromagnetic layer 32, a lower fixed magnetization stack 81, a lower nonmagnetic metal layer 37, a lower second diffusion prevention layer 38, a free layer. The magnetic layer 39, the upper first diffusion prevention layer 68, the upper nonmagnetic metal layer 67, the upper fixed magnetization stack 82, the upper antiferromagnetic layer 62, and the protective layer 40 are sequentially stacked. The lower pinned magnetization stack 81 includes a lower first pinned magnetization layer 34, a lower nonmagnetic coupling layer 35, a lower interface magnetic layer 83, a lower second pinned magnetization layer 56, and a lower second diffusion from the lower antiferromagnetic layer 32 side. The prevention layer 73 is laminated | stacked in order. The upper pinned magnetization stack 82 includes the upper second diffusion prevention layer 74, the upper second pinned magnetization layer 76, the upper interface magnetic layer 84, the upper nonmagnetic coupling layer 65, and the upper second magnetic layer 67 from the upper nonmagnetic metal layer 67 side. One fixed magnetization layer 64 is laminated in order. That is, in the GMR film 80, the lower interface magnetic layer 83 is provided between the lower nonmagnetic coupling layer 35 and the lower second fixed magnetic layer 56 of the fourth example GMR film 70 shown in FIG. The upper interface magnetic layer 84 is provided between the magnetization layer 76 and the upper nonmagnetic coupling layer 65.

  The lower interface magnetic layer 83 and the upper interface magnetic layer 84 are made of CoFeAl. By using CoFeAl, the lower second pinned magnetic layer 56 and the upper second diffusion prevention layer 74 made of Mn-based Heusler alloy are ferromagnetically coupled to the lower interface magnetic layer 83 and the upper interface magnetic layer 84, respectively. Therefore, the lower second pinned magnetization layer 56 and the upper second diffusion prevention layer 74 are antiferromagnetically coupled to the lower first pinned magnetization layer 34 and the upper first pinned magnetization layer 64 by stronger exchange interaction, respectively. Undesirable reversal of the magnetizations of the entire lower fixed magnetization stack 81 and the upper fixed magnetization stack 82 can be avoided. The film thicknesses of the lower interface magnetic layer 83 and the upper interface magnetic layer 84 are preferably set in the range of 0.2 nm to 2.5 nm, respectively. The lower interface magnetic layer 83 and the upper interface magnetic layer 84 may have the same composition ratio or different composition ratios.

  As described above, the GMR film 80 of the fifth example has the same effect as the GMR film of the fourth example, and further, the lower interface magnetic layer 83 and the upper interface magnetic layer 84 are provided, so that the entire lower fixed magnetization stack 81 is provided. Since the magnetization of the entire upper fixed magnetization stack 82 can be stabilized, the operation of the magnetoresistive element can be stabilized.

  Next, the diffusion preventing effect of the CoFeAl film will be described.

A magnetoresistive element having the following configuration is manufactured, and a magnetoresistive element in which the upper and lower surfaces of the Co ₅₈ Fe ₂₀ Al ₂₂ film are sandwiched between CoFe films (referred to as “prototype example 1”) and the amount of change in magnetoresistance is manufactured. The relationship between ΔRA and the thickness of the CoFe film was measured. For comparison, a magnetoresistive element in which the upper and lower surfaces of the Co ₂ MnGe film were sandwiched between CoFe films was fabricated (referred to as “prototype example 2”), and the above relationship was measured in the same manner.

[Prototype Example 1]
The following films were sequentially stacked on a thermally oxidized silicon substrate. Note that the film described on the right side of the same row is stacked on the left film. The numerical value in parentheses indicates the film thickness. The same applies to the following embodiments.

Lower electrode: Cu film (350 nm) / NiFe film (50 nm)
Underlayer: NiCr film (4 nm)
Lower antiferromagnetic layer: IrMn film (5 nm)
Lower first fixed magnetic layer: Co ₆₀ Fe ₄₀ film (3.5 nm)
Lower nonmagnetic coupling layer: Ru film (0.75 nm)
Interface CoFe film: Co ₄₀ Fe ₆₀ film Lower second fixed magnetic layer: Co ₅₈ Fe ₂₀ Al ₂₂ film Interface CoFe film Lower nonmagnetic metal layer: Cu film (3.5 nm)
Interfacial CoFe film Free magnetic layer: Co ₅₈ Fe ₂₀ Al ₂₂ film Interfacial CoFe film Upper nonmagnetic metal layer: Cu film (3.5 nm)
Interface CoFe film Upper second fixed magnetization layer: Co ₅₈ Fe ₂₀ Al ₂₂ film Interface CoFe film Upper nonmagnetic coupling layer: Ru film (0.75 nm)
Upper first fixed magnetic layer: Co ₆₀ Fe ₄₀ film (3.5 nm)
Upper antiferromagnetic layer: IrMn film (5 nm)
Protective layer: Ru film (5 nm)
The manufacturing method of the trial example 1 is as follows. A thermally oxidized silicon substrate is placed in a vacuum container of an ultra-high vacuum sputtering apparatus, and the above layers are formed without heating the substrate. The resulting laminate is laminated in the stacking direction by photolithography and ion milling. An element was formed so that a sense current could flow. Set element area to 0.1μm ² ~0.6μm ^2. The film thicknesses of the six interfacial CoFe films were simultaneously changed to 0 nm, 0.25 nm, 0.50 nm, 0.75 nm, and 1.00 nm. Further, depending on the thickness of the interface CoFe film, the thickness of the lower second fixed magnetization layer, the free magnetization layer, and the upper second fixed magnetization layer is changed, and the interface CoFe film / lower second fixed magnetization layer / interface CoFe film, The respective saturation magnetization film thickness products of the interface CoFe film / free magnetic layer / interface CoFe film, interface CoFe film / upper second fixed magnetization layer / interface CoFe film were made to be equal.

[Prototype example 2]
In the magnetoresistive effect element of Prototype Example 2, the lower second fixed magnetic layer, the free magnetic layer, and the upper second fixed magnetic layer of Prototype Example 1 are Co ₂ MnGe films, and the thickness of the interface CoFe film is 0 nm and 0.50 nm. , 0.75 nm, 1.00 nm, and 1.50 nm.

FIG. 7 is a diagram for explaining the degree of diffusion of the Co ₅₈ Fe ₂₀ Al ₂₂ film and the Co ₂ MnGe film into the Cu film.

Referring to FIG. 7, in Prototype Example 2 (Co ₂ MnGe film), the magnetoresistance change ΔRA is high when the thickness of the interface CoFe film is 1.0 nm, and the magnetism increases as the film thickness of the interface CoFe film decreases. When the resistance change amount ΔRA decreases and the interface CoFe film is not formed (when the film thickness is 0.0 nm), ΔRA is the lowest. Thereby, since the magnetoresistance change ΔRA decreases as the interface CoFe film becomes thinner, it is easily estimated that ΔRA is reduced by the diffusion of Mn of the Co ₂ MnGe film into the Cu film. The

On the other hand, in Prototype Example 1 (Co ₅₈ Fe ₂₀ Al ₂₂ film), the magnetoresistance change ΔRA is the smallest when the thickness of the interface CoFe film is 1.0 nm, and the magnetoresistance change as the thickness of the interface CoFe film is reduced. When ΔRA slightly increases and no interfacial CoFe film is formed (when the film thickness is 0.0 nm), ΔRA is the largest. This indicates that the Co ₅₈ Fe ₂₀ Al ₂₂ film does not diffuse into the Cu film even when there is no interfacial CoFe film, which makes the Co ₅₈ Fe ₂₀ Al ₂₂ film like Mn. It shows that it is possible to suppress diffusion of atoms that are easy to diffuse. From this, it was confirmed that the CoFeAl film used in the first to fifth examples described above has a diffusion preventing effect.

  Next, the advantage of forming the CoFeAl film in contact with the free magnetic layer over the CoFe film will be described.

[Prototype Example 3]
A laminated body having a structure in which the layers were laminated in the following order was produced, and the magnetic characteristics were measured with a vibrating sample magnetometer (VSM).

Ru film (5 nm) / Cu film (2 nm) / Co ₅₈ Fe ₂₀ Al ₂₂ film (10 nm) / Cu film (2 nm) / Ru film (5 nm)
The laminated body was formed by placing a thermal silicon oxide substrate on a vacuum container of an ultra-high vacuum sputtering apparatus and forming each of the above layers without heating the substrate.

For comparison, a laminate was similarly formed for a Co ₆₀ Fe ₄₀ film and a Co ₄₀ Fe ₆₀ film instead of the Co ₅₈ Fe ₂₀ Al ₂₂ film.

  FIG. 8 is a magnetic characteristic diagram of the CoFeAl film and the CoFe film. In FIG. 8, the bar graph indicates the saturation magnetic flux density, and the line graph indicates the coercive force.

Referring to FIG. 8, Co ₅₈ Fe ₂₀ Al ₂₂ film, to the Co ₆₀ Fe ₄₀ film and Co ₄₀ Fe ₆₀ film, not more than about 1/3 of the coercive force, Co ₅₈ Fe ₂₀ Al ₂₂ film The saturation magnetic flux density is approximately half. Thus, when the CoFeAl film is used as a diffusion preventing layer in contact with the free magnetic layer, it can be easily estimated that the CoFe film is advantageous because it has a lower coercive force than the CoFe film.

Further, since the CoFeAl film has a low saturation magnetic flux density, it has the following advantages. The magnetoresistive effect element is designed to set the saturation magnetic flux density film thickness to a predetermined value or less in order to ensure easy rotation of the magnetization of the free magnetic layer. For example, when the saturation magnetic flux density film thickness is set to 8 nm T, when the Co ₂ MnGe film (saturation magnetic flux density 1.3 T) is formed on the free magnetic layer and the diffusion prevention layers are formed on the upper and lower sides thereof with a film thickness of 1 nm, the diffusion prevention layer is In the Co ₆₀ Fe ₄₀ film (saturation magnetic flux density 2.0T), the thickness of the Co ₂ MnGe film of the Co ₆₀ Fe ₄₀ film / Co ₂ MnGe film / Co ₆₀ Fe ₄₀ film is set to 2.7 nm. . On the other hand, the Co ₅₈ Fe ₂₀ Al ₂₂ film (saturated magnetic flux density 1.0 T), but the Co ₂ MnGe film Co ₅₈ Fe ₂₀ Al ₂₂ film / Co ₂ MnGe film / Co ₅₈ Fe ₂₀ Al ₂₂ film laminate The film thickness is set to 4.6 nm. In other words, using the Co ₅₈ Fe ₂₀ Al ₂₂ film can increase the thickness of the Co ₂ MnGe film by 1.9 nm (= 4.6-2.7) compared to the Co ₆₀ Fe ₄₀ film. Therefore, when the Co ₅₈ Fe ₂₀ Al ₂₂ film is used, the Co ₂ MnGe film can be set thicker, so that a higher output magnetoresistive element can be formed. Even if the composition ratio of the CoFeAl film is different, the saturation magnetic flux density is substantially the same in the range of the composition range region ABCDEFA shown in FIG. 10, and thus the above-described advantages are not limited to the Co ₅₈ Fe ₂₀ Al ₂₂ film. The same applies even when CoFeAl films having different composition ratios are used.

[Prototype Example 4]
In Prototype Example 4, in order to obtain the relationship between the coercive force and the composition of a single CoFeAl film, a magnetoresistive effect element was manufactured using the CoFeAl film as a free magnetic layer. The coercive force was obtained from the hysteresis of the magnetoresistance curve of the magnetoresistive effect element.

  The configuration of the magnetoresistive effect element of Prototype Example 4 is as follows.

Underlayer: NiCr (4 nm)
Lower antiferromagnetic layer: IrMn (5 nm)
Lower first fixed magnetic layer: Co ₆₀ Fe ₄₀ (3.5 nm)
Lower nonmagnetic coupling layer: Ru (0.72 nm)
Lower second fixed magnetic layer: CoFeAl (5.0 nm)
Lower nonmagnetic metal layer: Cu (3.5 nm)
Free magnetic layer: CoFeAl (6.5 nm)
Upper nonmagnetic metal layer: Cu (3.5 nm)
Upper second fixed magnetic layer: CoFeAl (5.0 nm)
Upper nonmagnetic coupling layer: Ru (0.72 nm)
Upper first fixed magnetic layer: Co ₆₀ Fe ₄₀ (3.5 nm)
Upper antiferromagnetic layer: IrMn (5 nm)
Protective layer: Ru (5 nm)
FIG. 9 is a diagram showing the composition and coercivity of the free magnetic layer, the lower and upper second fixed magnetic layers of Prototype Example 4.

  The magnetoresistive effect element of Prototype Example 4 was produced and measured for coercive force as follows. As a sample of Prototype Example 4, as shown in FIG. 1-No. 27 samples were produced.

First, a Cu (250 nm) / NiFe (50 nm) laminated film is formed as a lower electrode on a silicon substrate on which a thermal oxide film is formed from the silicon substrate side, and then an underlayer having the following composition and film thickness: Each layer of the laminate up to the protective layer was formed in a super high vacuum (degree of vacuum: 2 × 10 ⁻⁶ Pa or less) atmosphere using a sputtering apparatus without heating the substrate. In each sample, the composition of CoFeAl in the lower second fixed magnetic layer, the free magnetic layer, and the upper second fixed magnetic layer is the same, and the compositions are shown in FIG.

  Next, heat treatment was performed to make the antiferromagnetic layer appear antiferromagnetic. The heat treatment conditions were a heating temperature of 300 ° C., a treatment time of 3 hours, and an applied magnetic field of 1952 kA / m.

Then, the thus obtained laminate was ground by ion milling, to produce a laminate, having six junction area in the range of 0.1μm ² ~0.6μm ^2. In addition, 40 laminated bodies were produced for each bonding area.

  Next, the laminated body thus obtained was covered with a silicon oxide film, then the protective layer was exposed by dry etching, and an upper electrode made of an Au film was formed so as to be in contact with the protective layer.

  Sample No. obtained in this way. 1-No. For each of 27, a magnetoresistance curve (hysteresis curve, relationship between magnetoresistance change ΔR value and applied magnetic field) was measured. Specifically, this measurement was performed for the following purposes. The current value of the sense current is set to 2 mA, the external magnetic field is swept in the range of −7.9 kA / m to 7.9 kA / m in parallel with the magnetization direction of the lower and upper second fixed magnetization layers, and the lower electrode and the upper electrode The voltage between the electrodes was measured with a digital voltmeter to obtain a magnetoresistance curve (hysteresis curve). And the coercive force was calculated | required from this hysteresis curve. Sample No. obtained in this way. 1-No. The coercivity of 27 is as shown in FIG.

  FIG. 10 is a relationship diagram between the coercive force and the composition of the CoFeAl film of Prototype Example 4. FIG. 10 shows the composition of the ternary system of Co, Fe, and Al with the sample No. shown in FIG. The coercive force (unit: Oe) of the free magnetic layers 1 to 27 is shown numerically in accordance with the composition coordinates.

Referring to FIG. 10, the coercive force of the free magnetic layer is such that Co ₅₀ Fe ₂₅ Al ₂₅ , which is a composition of Heusler alloy, has a coercive force of 30.5 Oe, whereas the Co content is higher, and Fe It turns out that it is low with the composition of the side with less content. However, when the Co content is 80 atomic% and the Al content is 25 atomic%, the coercive force of the free magnetic layer increases.

  From this result, the composition range for setting the coercive force of the CoFeAl film to 30 Oe or less is represented by a point A (55, 10, and 5) when the coordinates of each composition are expressed as (Co content, Fe content, Al content). 35), point B (50, 15, 35), point C (50, 20, 30), point D (55, 25, 20), point E (60, 25, 15), point F (70, 15, 15), in the area ABCDEFA where the points A, B, C, D, E, F, and A are connected in this order by a straight line (area surrounded by the solid solid line in FIG. 10). It can be seen that the composition should be set.

  Furthermore, the composition ranges for setting the coercivity of the CoFeAl film to 20 Oe or less are point A (55, 10, 35), point B (50, 15, 35), point C (50, 20, 30), point As G (65, 20, 15), the composition of a region ABCGA (region surrounded by a thick broken line in FIG. 10) in which points A, B, C, G, and A are connected in a straight line in this order. It turns out that it should just set to.

  By using the CoFeAl film having the composition range obtained as described above for the diffusion preventing layer in contact with the free magnetic layer, the coercive force as a laminated body of the free magnetic layer and the diffusion preventing layer can be reduced.

(Second Embodiment)
In the magnetic head according to the second embodiment of the present invention, the magnetoresistive element has a tunnel magnetoresistive (hereinafter referred to as “TMR”) film. The configuration of the magnetic head according to the second embodiment is substantially the same except that a TMR film is provided instead of the GMR film 30 constituting the magnetoresistive effect element 20 of the magnetic head 10 shown in FIG. Description of the magnetic head is omitted. Hereinafter, five examples (first to fourth examples) of the TMR film constituting the magnetoresistive element 20 will be described. Any of the TMR films of the first to fourth examples may be applied to the magnetoresistive effect element 20.

[TMR film of first example]
FIG. 11 is a sectional view of the TMR film of the first example constituting the magnetoresistive effect element according to the second embodiment of the present invention. In the figure, portions corresponding to the portions described above are denoted by the same reference numerals, and description thereof is omitted.

  Referring to FIG. 11, the TMR film 91 of the first example includes an underlayer 31, an antiferromagnetic layer 32, a fixed magnetization stack 33, a nonmagnetic insulating layer 37a, a first diffusion prevention layer 38, a free magnetization layer 39, The third diffusion preventing layer 41 and the protective layer 40 are sequentially stacked.

  The TMR film 91 is the same as the GMR film 30 shown in FIG. 2 except that the nonmagnetic metal layer 37 is replaced with a nonmagnetic insulating layer 37a made of an insulating material and a third diffusion prevention layer 41 is further formed. Consists of configuration. In the TMR film 91, the nonmagnetic insulating layer 37 a is provided between the free magnetic layer 39 and the second pinned magnetic layer 36, so that the magnetization direction of the free magnetic layer 39 with respect to the magnetization direction of the second pinned magnetic layer 36 is changed. A ferromagnetic tunnel effect is generated according to the angle formed, and the electric resistance value between the free magnetic layer 39 and the second pinned magnetic layer 36 changes.

  The nonmagnetic insulating layer 37a has a thickness of 0.2 nm to 2.0 nm, for example, and is made of any one oxide of the group consisting of Mg, Al, Ti, and Zr. Examples of such oxides include MgO, AlOx, TiOx, and ZrOx. Here, x indicates that the composition may deviate from the composition of the compound of each material. In particular, the nonmagnetic insulating layer 37a is preferably made of crystalline MgO, and in particular, the tunnel resistance change amount of the unit area of the film surface perpendicular to the sense current direction (hereinafter referred to as “tunnel resistance change amount unless otherwise specified”). It is preferable that the (001) plane of MgO is substantially parallel to the film plane. Further, the nonmagnetic insulating film 37a may be made of any one nitride or oxynitride selected from the group consisting of Al, Ti, and Zr. Examples of such nitride include AlN, TiN, and ZrN.

  As a method for forming the nonmagnetic insulating film 37a, the above-described materials may be directly formed using a sputtering method, a CVD method, or a vapor deposition method. After forming a metal film using a sputtering method, a CVD method, or a vapor deposition method, oxidation is performed. It may be converted into an oxide film or nitride film by performing treatment or nitriding treatment. Note that the upper nonmagnetic insulating layer 67a of the TMR film of the third example shown in FIG. 13 will be formed later by the same method as the nonmagnetic insulating film 37a.

  The tunnel resistance change amount is obtained in the same manner as the measurement of the magnetoresistance change amount ΔRA of the unit area of the first embodiment. The amount of tunnel resistance change increases as the polarizabilities of the free magnetic layer 39 and the second pinned magnetic layer 36 increase. The polarizability is a polarizability of a ferromagnetic layer (free magnetic layer 39 or second pinned magnetic layer 36) through an insulating layer (nonmagnetic insulating film 37a). Since the spin-dependent bulk scattering coefficient of the Mn-based Heusler alloy is the same as or larger than that of the CoFe film, the unit area can be obtained by using the Mn-based Heusler alloy for the free magnetic layer 39 as in the first embodiment. The amount of tunnel resistance change can be increased.

  The first diffusion prevention layer 38 and the third diffusion prevention layer 41 are made of CoFeAl similar to that described in the first embodiment. Thereby, diffusion of Mn from the free magnetic layer 39 to the nonmagnetic insulating layer 37a and the protective film 40 can be suppressed.

  As described above, the TMR film 91 of the first example is provided with the diffusion preventing layer 38 made of CoFeAl between the free magnetic layer 39, the nonmagnetic insulating layer 37 a, and the protective film 40. It prevents the Mn atom of the Heusler alloy from diffusing into the nonmagnetic insulating layer 37a and the protective film 40 more completely. In addition, the spin-dependent bulk scattering of the Mn-based Heusler alloy is larger than that of CoFe, and the CoFeAl film has a lower saturation magnetic flux density than that of CoFe. Therefore, the thickness of the free magnetic layer 39 can be increased. Therefore, a high-output magnetoresistive element can be obtained.

At the same time, in the TMR film 91 of the first example, the diffusion prevention layer 38 and the third diffusion prevention layer 41 are provided in contact with the upper and lower sides of the free magnetic layer 39, so And the magnetization of the free magnetic layer 39 respond to an external magnetic field while being exchange coupled with each other. Since CoFeAl of the diffusion prevention layer 38 and the third diffusion prevention layer 41 has a lower coercive force and a lower saturation magnetic flux density than CoFe, the magnetizations of the diffusion prevention layer 38, the third diffusion prevention layer 41, and the free magnetization layer 39 are sensitive to an external magnetic field. Will improve. As a result, a magnetoresistive element having high output and good sensitivity to an external magnetic field can be obtained.
[TMR film of the second example]
Next, a TMR film of a second example constituting the magnetoresistive effect element according to the second embodiment will be described. The TMR film of the second example is a modification of the TMR film 91 of the first example shown in FIG.

  FIG. 11 is a cross-sectional view of a TMR film of a second example constituting the magnetoresistive effect element according to the second embodiment. In the figure, portions corresponding to the portions described above are denoted by the same reference numerals, and description thereof is omitted.

  Referring to FIG. 11, the TMR film 92 of the second example includes an underlayer 31, an antiferromagnetic layer 32, a fixed magnetization stack 53, a second diffusion prevention layer 51, a nonmagnetic insulating layer 37a, and a first diffusion prevention layer. 38, a free magnetic layer 39, a third diffusion prevention layer 41, and a protective layer 40 are sequentially stacked. The fixed magnetization stack 53 is formed by sequentially stacking a first fixed magnetization layer 34, a nonmagnetic coupling layer 35, and a second fixed magnetization layer 56 from the antiferromagnetic layer 32 side.

  In the TMR film 92 of the second example, the second pinned magnetic layer 56 is made of a Mn-based Heusler alloy, and the second diffusion prevention layer 51 is provided between the second pinned magnetic layer 56 and the nonmagnetic insulating layer 37a. Except for this, it has the same configuration as the TMR film of the first example of FIG.

In the TMR film 92, since the second pinned magnetic layer 56 is made of a Mn-based Heusler alloy, the tunnel resistance change amount can be made larger than that of the TMR film of the first example. Further, a first diffusion preventing layer 38 is provided between the nonmagnetic insulating layer 37a and the free magnetic layer 39, and a second diffusion preventing layer 51 is provided between the second pinned magnetic layer 56 and the nonmagnetic insulating layer 37a. Since the third diffusion prevention layer 41 is provided between the magnetic layer 39 and the protective film 40, as described in the first embodiment, the Mn of the free magnetic layer 39 and the second pinned magnetic layer 56 Diffusion can be prevented more completely. In particular, when the TMR film 91 is exposed to a high temperature in the heat treatment in a magnetic field, Mn is easily diffused, but the Mn diffusion can be prevented by the first to third diffusion preventing layers 38, 51, and 41. Also,
As described above, the TMR film 92 of the second example has the same effect as that of the TMR film of the first example, and the second pinned magnetic layer 56 is made of a Mn-based Heusler alloy, so that the amount of change in tunnel resistance is increased. it can. Therefore, it is possible to realize a magnetoresistive element having high output and good sensitivity to a signal magnetic field.
[TMR film of third example]
Next, a third example TMR film constituting the magnetoresistive effect element according to the second embodiment will be described. The TMR film of the third example is a modification of the TMR film 91 of the first example shown in FIG.

  FIG. 13 is a cross-sectional view of a third example TMR film constituting the magnetoresistive effect element according to the second embodiment. In the figure, portions corresponding to the portions described above are denoted by the same reference numerals, and description thereof is omitted.

  Referring to FIG. 13, the TMR film 93 of the third example includes an underlayer 31, a lower antiferromagnetic layer 32, a lower fixed magnetization stack 33, a lower nonmagnetic insulating layer 37a, a lower diffusion prevention layer 38, a free magnetization layer. 39, an upper diffusion prevention layer 68, an upper nonmagnetic insulating layer 67a, an upper fixed magnetization stack 63, an upper antiferromagnetic layer 62, and a protective layer 40 are sequentially stacked. That is, the TMR film 93 includes an upper diffusion prevention layer 68, an upper nonmagnetic insulating layer 67a, and an upper fixed magnetization stack between the free magnetic layer 39 and the protective layer 40 of the TMR film 91 of the first example shown in FIG. 63, and an upper antiferromagnetic layer 62 is provided.

  The lower antiferromagnetic layer 32, the lower fixed magnetization stack 33, the lower nonmagnetic insulating layer 37a, and the lower diffusion prevention layer 38 are each an antiferromagnetic layer 32 of the TMR film 90 of the first example shown in FIG. Since the fixed magnetic layer 33, the nonmagnetic insulating layer 37a, and the first diffusion prevention layer 38 have the same material and film thickness, the same reference numerals are used. The upper diffusion preventing layer 68, the upper nonmagnetic insulating layer 67a, and the upper antiferromagnetic layer 62 are made of the same material as the lower diffusion preventing layer 38, the lower nonmagnetic insulating layer 37a, and the lower antiferromagnetic layer 32, respectively. The film thickness can be set in the same range.

  The upper pinned magnetization stack 63 is formed by sequentially stacking an upper second pinned magnetization layer 66, an upper nonmagnetic coupling layer 65, and an upper first pinned magnetization layer 64 from the upper nonmagnetic insulating layer 67a side. Has a ferri structure. The upper first pinned magnetization layer 64, the upper nonmagnetic coupling layer 65, and the upper second pinned magnetization layer 66 are the lower first pinned magnetization layer 34, the lower nonmagnetic coupling layer 35, and the lower second pinned magnetization layer 36, respectively. The same material can be used, and the film thickness is also set in the same range.

  Since the TMR film 93 has a dual spin valve structure, the amount of change in tunnel resistance increases, which is approximately twice the amount of change in tunnel resistance of the TMR film of the first example.

  As described above, the TMR film 93 of the third example can realize a magnetoresistive effect element with higher output.

[TMR film of fourth example]
Next, a fourth example TMR film constituting the magnetoresistive effect element according to the second embodiment will be described. The TMR film of the fourth example is a modification of the TMR film of the third example shown in FIG.

  FIG. 14 is a cross-sectional view of a fourth example TMR film constituting the magnetoresistive effect element according to the second embodiment. In the figure, portions corresponding to the portions described above are denoted by the same reference numerals, and description thereof is omitted.

  Referring to FIG. 14, in the TMR film 94 of the fourth example, the lower second pinned magnetic layer 56 is made of a Mn-based Heusler alloy, and the CoFeAl layer is interposed between the lower nonmagnetic coupling layer 35 and the lower second pinned magnetic layer 56. A lower interfacial magnetic layer 83 is provided, and a lower second diffusion prevention layer 73 is provided between the lower second pinned magnetic layer 56 and the lower nonmagnetic insulating layer 37a. In the TMR film 94, the upper second pinned magnetic layer 66 is made of a Mn-based Heusler alloy, and the upper second diffusion preventing layer 74 made of CoFeAl between the upper nonmagnetic insulating layer 67a and the upper second pinned magnetic layer 76. The upper interface magnetic layer 84 is provided between the upper second pinned magnetic layer 66 and the upper nonmagnetic coupling layer 65. Other configurations are the same as those of the TMR film 93 of the third example shown in FIG.

  Since the lower second pinned magnetic layer 56 and the upper second pinned magnetic layer 66 are made of a Mn-based Heusler alloy, the amount of change in tunnel resistance is large. Furthermore, by providing the lower second diffusion prevention layer 73 and the upper second diffusion prevention layer 74, Mn diffusion of the lower second fixed magnetization layer 56 and the upper second fixed magnetization layer 66 can be more completely prevented.

  Further, the lower interface magnetic layer 83 and the upper interface magnetic layer 84 are respectively the same materials as the lower interface magnetic layer 83 and the upper interface magnetic layer 84 of the GMR film 80 of the fifth example of the first embodiment of FIG. And a film thickness. Thereby, undesired reversal of the magnetization of the entire lower fixed magnetization stack 81 and the upper fixed magnetization stack 82 can be avoided.

  As described above, the TMR film 94 of the fifth example has the same effect as the TMR film of the fourth example, and the amount of change in tunnel resistance further increases. In addition, since the magnetization of the entire lower fixed magnetization stack 81 and the entire upper fixed magnetization stack 82 can be stabilized, the operation of the magnetoresistive effect element can be stabilized.

(Third embodiment)
FIG. 15 is a plan view showing a main part of a magnetic memory device according to the third embodiment of the present invention.

  Referring to FIG. 15, the magnetic storage device 100 generally includes a housing 101. In the housing 101, a hub 102 driven by a spindle (not shown), a magnetic recording medium 103 fixed to the hub 102 and rotated by the spindle, an actuator unit 104, and supported by the actuator unit 104, the magnetic recording medium 103 A radially driven arm 105, a suspension 106, and a magnetic head 108 supported by the suspension 106 are provided.

  The magnetic recording medium 103 may be either a longitudinal magnetic recording system or a perpendicular magnetic recording system, or a recording medium having oblique anisotropy. The magnetic recording medium 103 is not limited to a magnetic disk but may be a magnetic tape.

  As shown in FIG. 1, the magnetic head 108 includes a magnetoresistive effect element 20 formed on a ceramic substrate and an inductive recording element 13 formed thereon. The inductive recording element 13 may be a ring-type recording element for in-plane recording, a single-pole recording element for perpendicular magnetic recording, or another known recording element. The magnetoresistive effect element 20 is the GMR film of any one of the first to fifth examples of the first embodiment or the TMR film of any of the first to fourth examples of the second embodiment. Prepare. Therefore, the magnetoresistive effect element has high output and good sensitivity to the signal magnetic field. Therefore, the magnetic storage device 100 is suitable for high recording density recording. Note that the basic configuration of the magnetic storage device 100 according to the present embodiment is not limited to that shown in FIG.

(Fourth embodiment)
FIG. 16A is a cross-sectional view of the first example of the magnetic memory device according to the fourth embodiment of the present invention, and FIG. 16B is a configuration diagram of the GMR film shown in FIG. FIG. 17 is an equivalent circuit diagram of one memory cell of the magnetic memory device of the first example. In FIG. 16A, orthogonal coordinate axes are shown together to indicate directions. Among these, the Y ₁ and Y ₂ directions are directions perpendicular to the paper surface, the Y ₁ direction is a direction toward the back of the paper surface, and the Y ₂ direction is a direction toward the front of the paper surface. In the following description, for example, simply referring to the X direction indicates that either the X ₁ direction or the X ₂ direction may be used, and the same applies to the Y direction and the Z direction. In the figure, portions corresponding to the portions described above are denoted by the same reference numerals, and description thereof is omitted.

  Referring to FIGS. 16A, 16B, and 17, the magnetic memory device 110 includes a plurality of memory cells 111 arranged in a matrix, for example. The memory cell 111 is roughly composed of a magnetoresistive effect (GMR) film 30 and a MOS field effect transistor (FET) 112. Note that a p-channel MOS type FET or an n-channel MOS type FET can be used as the MOS type FET. Here, an n-channel MOS type FET in which electrons are carriers will be described as an example.

  The MOS FET 112 is an impurity in which an n-type impurity is introduced in the vicinity of the surface of the silicon substrate 113 in the p-well region 114 and the p-well region 114 containing the p-type impurity formed in the silicon substrate 113. Diffusion regions 115a and 115b are provided. Here, one impurity diffusion region 115a is a source S, and the other impurity diffusion region 115b is a drain D. In the MOS FET 112, a gate electrode G is provided on the surface of the silicon substrate 113 between the two impurity diffusion regions 115a and 115b via a gate insulating film 116.

  The source S of the MOS FET 112 is electrically connected to one side of the GMR film 30, for example, the base layer 31, via the vertical wiring 124 and the intralayer wiring 125. Further, the plate line 118 is electrically connected to the drain D through the vertical wiring 124. The gate electrode G is electrically connected to the read word line 119. Note that the gate electrode G may also serve as the read word line 119.

  The bit line 120 is electrically connected to the other side of the GMR film 30, for example, the protective layer 40. A write word line 121 is provided below the GMR film 30 at a distance.

  The GMR film 30 has the same configuration as the GMR film 30 shown in FIG. In the GMR film 30, the direction of the easy axis of the free magnetic layer 39 is set along the X-axis direction shown in FIG. 16A, and the direction of the hard axis is set along the Y direction. The direction of the easy axis of magnetization may be formed by heat treatment or by shape anisotropy. When the easy magnetization axis is formed in the X-axis direction due to the shape anisotropy, the cross-sectional shape parallel to the film surface of the GMR film 30 (the cross-sectional shape parallel to the XY plane) is set in the X direction rather than the Y-direction side. A rectangle with a long side.

  In the magnetic memory device 110, the surface of the silicon substrate 113 and the gate electrode G are covered with an interlayer insulating film 123 such as a silicon nitride film or a silicon oxide film. In addition, the GMR film 30, the plate line 118, the read word line 119, the bit line 120, the write word line 121, the vertical wiring 124, and the intra-layer wiring 125 are interlayer-insulated except for the electrical connection described above. The films 123 are electrically insulated from each other.

  The magnetic memory device 110 holds information in the GMR film 30. Information is held depending on whether the magnetization direction of the free magnetic layer 39 is parallel or antiparallel to the magnetization direction of the second pinned magnetic layer 36.

  Next, write and read operations of the magnetic memory device 110 will be described. The information write operation to the GMR film 30 of the magnetic memory device 110 is performed by the bit line 120 and the write word line 121 arranged above and below the GMR film 30. The bit line 120 extends above the GMR film 30 in the X direction, and is applied to the GMR film 30 in the Y direction by passing a current through the bit line 120. The write word line 121 extends below the GMR film 30 in the Y direction, and a magnetic field is applied to the GMR film 30 in the X direction by passing a current through the write word line 121.

When the magnetic field is not substantially applied, the magnetization of the free magnetic layer 39 of the GMR film 30 faces the X direction (for example, the X ₂ direction), and the magnetization direction is stable.

When writing information to the GMR film 30, a current is simultaneously applied to the bit line 120 and the write word line 121. For example, when the magnetization of the free magnetic layer 39 is directed in the X ₁ direction, a current flowing through the write word line 121 is passed in the Y ₁ direction. Thus, the magnetic field in the GMR film 30 is X ₁ direction. At this time, the direction of the current flowing through the bit line 120 may be either the X ₁ direction or the X ₂ direction. The magnetic field generated by the current flowing through the bit line 120 is in the Y ₁ direction or Y ₂ direction in the GMR film 30 and functions as part of the magnetic field for the magnetization of the free magnetic layer 39 to cross the barrier of the hard axis. That is, when the magnetic field in the X ₁ direction and the Y ₁ direction or the Y ₂ direction are simultaneously applied to the magnetization of the free magnetic layer 39, the magnetization of the free magnetic layer 39 facing the X ₂ direction becomes the X ₁ direction. Invert to. And also the magnetization of the free magnetization layer 39 after removal of the magnetic field is oriented in the X ₁ direction, as long as the magnetic field or magnetic field for erasing the next write operation is not applied is stable.

In this way, “1” or “0” can be recorded in the GMR film 30 according to the magnetization direction of the free magnetic layer 39. For example, when the magnetization direction of the second pinned magnetic layer 36 is the X ₁ direction, when the magnetization direction of the free magnetic layer 39 is the X ₁ direction (the tunnel resistance value is low), “1”, the X ₂ direction ( When the tunnel resistance value is high), it is set to “0”.

  Note that the magnitude of the current supplied to the bit line 120 and the write word line 121 during the write operation is such that the free magnetization is applied even if the current flows only in either the bit line 120 or the write word line 121. It is set to such an extent that the magnetization reversal of the layer 39 does not occur. As a result, recording is performed only on the magnetization of the free magnetic layer 39 of the GMR film 30 at the intersection of the bit line 120 supplied with current and the write word line 121 supplied with current. Note that the source S side is set to high impedance so that no current flows through the GMR film 30 when a current is passed through the bit line 120 during the write operation.

  Next, in the information read operation to the GMR film 30 of the magnetic memory device 110, a negative voltage is applied to the bit line 120 with respect to the source S, and the threshold value of the MOS FET 112 is applied to the read word line 119, that is, the gate electrode G. This is performed by applying a voltage (positive voltage) larger than the voltage. As a result, the MOS FET 112 is turned on, and electrons flow from the bit line 120 to the plate line 118 through the GMR film 30, the source S, and the drain D. By electrically connecting a current value detector 128 such as an ammeter to the plate line 118, a magnetoresistance value corresponding to the magnetization direction of the free magnetization layer 39 relative to the magnetization direction of the second pinned magnetization layer 36 is detected. . Thereby, “1” or “0” information held by the GMR film 30 can be read.

  In the magnetic memory device 110 of the first example according to the fourth embodiment, since the free magnetic layer 39 of the GMR film 30 is made of an Mn-based Heusler alloy, the magnetoresistance change ΔRA is large. Therefore, the magnetic memory device 110 can read data accurately because there is a large difference in the magnetoresistive values corresponding to the stored “0” and “1” when reading information. Further, as described in the first embodiment, the GMR film 30 uses the CoFeAl of the diffusion prevention layer 38 provided in contact with the free magnetization layer 39, so that the free magnetization layer 39 and the diffusion prevention layer 38 are formed. The coercivity of the laminate is low. Therefore, the magnetic memory device 110 can reduce the magnetic field applied during the write operation. Therefore, the current value flowing through the bit line 120 and the write word line 121 during the write operation can be reduced, so that the power consumption of the magnetic memory device 110 can be reduced.

  Further, since the GMR film 30 has the diffusion prevention layer 38 between the nonmagnetic metal layer 37 and the free magnetic layer 39, the diffusion of Mn contained in the free magnetic layer 39 into the nonmagnetic metal layer 37 is prevented. Therefore, the deterioration of ΔRA of the GMR film 30 can be prevented. Since CoFeAl is used for the diffusion preventing layer 38, an increase in ΔRA and a decrease in the coercive force of the laminated body of the free magnetic layer 39 and the diffusion preventing layer 38 can be realized at the same time. As a result, the magnetic memory device 110 can reduce the magnetic field applied during the write operation. Therefore, the current value flowing through the bit line 120 and the write word line 121 during the write operation can be reduced, so that the power consumption of the magnetic memory device 110 can be reduced.

  The GMR film 30 constituting the magnetic memory device 110 may be replaced with any of the GMR films 50, 60, 70, 80 of the second to fifth examples shown in FIGS. Modifications in the description of the GMR films 30, 50, 60, 70, 80 of the first to fifth examples may be used.

  FIG. 18 is a configuration diagram of a TMR film constituting a modification of the magnetic memory device of the first example. Referring to FIG. 18 together with FIG. 16A, a TMR film 91 may be used instead of the GMR film 30 constituting the magnetic memory device 110. The TMR film 91 has the same configuration as the TMR film 91 of the first example that constitutes the magnetoresistive effect element according to the second embodiment shown in FIG. In the TMR film 91, for example, the base layer 31 is in contact with the in-layer wiring 125 and the protective layer 40 is in contact with the bit line 120. The easy axis of the free magnetic layer 39 is arranged in the same manner as the GMR film 30 described above. Since the write operation and the read operation of the magnetic memory device 110 using the TMR film 91 are the same as those of the GMR film, the description thereof is omitted.

  The TMR film 91 exhibits a tunnel resistance effect as described in the second embodiment. The TMR film 91 has a large amount of change in tunnel resistance because the free magnetic layer 39 is made of a Mn-based Heusler alloy. Therefore, the magnetic memory device 110 can read data accurately because the tunnel resistance change amount corresponding to the stored “0” and “1” is large when reading information. Furthermore, since the coercive force of the free magnetic layer 39 is reduced, the sensitivity is high and the power consumption of the magnetic memory device 110 can be reduced.

  As the TMR film 91 constituting the magnetic memory device 110, the TMR films 92 to 94 of the second to fourth examples shown in FIGS. 12 to 14 may be used. Further, the TMR films 91 to 94 of the first to fourth examples may be used. Modifications in the description of the TMR films 91 to 94 may be used.

  FIG. 19 is a cross-sectional view of a magnetic memory device of a second example according to the fourth embodiment. In the figure, portions corresponding to the portions described above are denoted by the same reference numerals, and description thereof is omitted.

  Referring to FIG. 19, the magnetic memory device 130 is different from the magnetic memory device of the first example in the mechanism for writing information to the GMR film 30. The memory cell of the magnetic memory device 130 has the same configuration as the memory cell 111 shown in FIGS. 16A and 16B except that the write word line 121 is not provided.

  Hereinafter, description will be made with reference to FIG. The magnetic memory device 130 is different in write operation from the magnetic memory device of the first example. The magnetic memory device 130 injects the polarized spin current Iw into the GMR film 30, and the magnetization direction of the free magnetic layer 39 is parallel to the magnetization direction of the second pinned magnetic layer 36 depending on the direction of the current. From anti-parallel to anti-parallel or from anti-parallel to parallel. The polarized spin current Iw is an electron flow composed of electrons in one of two spin directions that can be taken by electrons. By causing the direction of the polarized spin current Iw to flow below or above the GMR film 30, a torque is generated in the magnetization of the free magnetic layer, thereby causing a so-called spin injection magnetization reversal. The amount of the polarized spin current Iw is appropriately selected according to the film thickness of the free magnetic layer 39, but is about several mA to 20 mA. The amount of polarized spin current Iw is smaller than the amount of current that flows through bit line 120 and write word line 121 during the write operation of the magnetic memory device of the first example of FIG. Can be reduced.

  The polarized spin current can be generated by flowing a current perpendicularly to a stacked body having a structure substantially similar to that of the GMR film 30 and sandwiching a Cu film between two ferromagnetic layers. The direction of electron spin can be controlled by setting the magnetization directions of the two ferromagnetic layers to be parallel or antiparallel. The reading operation of the magnetic memory device 130 is the same as that of the magnetic memory device 110 of the first example in FIG.

  The magnetic memory device 130 of the second example has the same effect as the magnetic memory device of the first example. Furthermore, the magnetic memory device 130 of the second example can reduce the amount of current during the write operation as compared with the magnetic memory device of the first example, and thus can reduce power consumption.

  The magnetic memory device 130 may be replaced with any of the GMR films 50, 60, 70, 80 of the second to fifth examples shown in FIGS. 3 to 6 instead of the GMR film 30, or The TMR films 91 to 94 of the first to fourth examples shown in FIGS. 11 to 14 may be substituted, and further, the GMR film or the TMR film of the modified examples in these descriptions may be substituted.

  Further, in the magnetic memory devices 110 and 130 of the first and second examples of the fourth embodiment, the current control during the write operation and the read operation is performed by the MOS type FET 112, but other known means Current control may be performed by

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the present invention described in the claims. It can be changed.

  For example, in the third embodiment, the case where the magnetic recording medium is disk-shaped has been described as an example. However, it goes without saying that the present invention can also be applied to a magnetic tape device in which the magnetic recording medium is tape-shaped. Further, the magnetic head including the magnetoresistive effect element and the recording element has been described as an example, but a magnetic head including only the magnetoresistive effect element may be used. Furthermore, a magnetic head in which a plurality of magnetoresistive elements are arranged may be used.

In addition, the following additional notes are disclosed regarding the above description.
(Appendix 1)
A CPP type magnetoresistive element,
A fixed magnetization layer, a nonmagnetic metal layer, a diffusion prevention layer, and a free magnetization layer are laminated in this order,
The free magnetic layer is made of a Mn-based Heusler alloy,
2. The magnetoresistive element according to claim 1, wherein the diffusion preventing layer is made of CoFeAl.
(Appendix 2)
Another diffusion preventing layer and a protective layer are further laminated in this order on the free magnetic layer,
The magnetoresistive effect element according to appendix 1, wherein the other diffusion prevention layer is made of CoFeAl.
(Appendix 3)
3. The magnetoresistive effect element according to appendix 1 or 2, wherein another diffusion prevention layer, another nonmagnetic metal layer, and another fixed magnetization layer are further laminated on the free magnetization layer.
(Appendix 4)
The fixed magnetization layer is formed by laminating a first fixed magnetization layer, a nonmagnetic coupling layer, and a second fixed magnetization layer in this order, and the second fixed magnetization layer and the nonmagnetic metal layer In addition, another diffusion prevention layer is provided between
The second pinned magnetic layer is made of a Mn-based Heusler alloy;
The magnetoresistive effect element according to any one of appendices 1 to 3, wherein the other diffusion preventing layer is made of CoFeAl.
(Appendix 5)
The magnetoresistive element according to claim 4, further comprising the other diffusion prevention layer between the nonmagnetic coupling layer and the second pinned magnetization layer.
(Appendix 6)
The other pinned magnetic layer is formed by stacking another second pinned magnetic layer, another nonmagnetic coupling layer, and another first pinned magnetic layer in this order. Further comprising another diffusion prevention layer between the fixed magnetization layer and the other nonmagnetic metal layer,
The second pinned magnetic layer is made of a Mn-based Heusler alloy;
The magnetoresistive effect element according to any one of appendices 3 to 5, wherein the other diffusion preventing layer is made of CoFeAl.
(Appendix 7)
The magnetoresistive element according to claim 6, further comprising the other diffusion prevention layer between the other second pinned magnetic layer and the other nonmagnetic coupling layer.
(Appendix 8)
A CPP type magnetoresistive element,
A fixed magnetic layer, a nonmagnetic insulating layer, a free magnetic layer, another diffusion prevention layer, and a protective layer are laminated in this order,
The protective layer is made of a nonmagnetic metal material,
The free magnetic layer is made of a Mn-based Heusler alloy,
The other diffusion preventing layer is made of CoFeAl.
(Appendix 9)
9. The magnetoresistive element according to appendix 8, wherein the protective layer has a Cu film in contact with another diffusion prevention layer.
(Appendix 10)
Further comprising a diffusion prevention layer between the nonmagnetic insulating layer and the free magnetic layer,
10. The magnetoresistive effect element according to appendix 8 or 9, wherein the diffusion preventing layer is made of CoFeAl.
(Appendix 11)
Any one of Supplementary notes 8 to 10, wherein another nonmagnetic insulating layer and another pinned magnetic layer are further laminated on the other diffusion prevention layer instead of the protective layer. The magnetoresistive effect element as described.
(Appendix 12)
The fixed magnetization layer is formed by laminating a first fixed magnetization layer, a nonmagnetic coupling layer, and a second fixed magnetization layer in this order, and the second fixed magnetization layer and the nonmagnetic insulating layer In addition, another diffusion prevention layer is provided between
The second pinned magnetic layer is made of a Mn-based Heusler alloy;
The magnetoresistive effect element according to any one of appendices 8 to 11, wherein the other diffusion preventing layer is made of CoFeAl.
(Appendix 13)
13. The magnetoresistive effect element according to appendix 12, further comprising the other diffusion prevention layer between the nonmagnetic coupling layer and the second pinned magnetization layer.
(Appendix 14)
The other pinned magnetic layer is formed by stacking another second pinned magnetic layer, another nonmagnetic coupling layer, and another first pinned magnetic layer in this order. Further comprising another diffusion prevention layer between the fixed magnetization layer and the other nonmagnetic insulating layer,
The second pinned magnetic layer is made of a Mn-based Heusler alloy;
14. The magnetoresistive element according to any one of appendices 8 to 13, wherein the other diffusion preventing layer is made of CoFeAl.
(Appendix 15)
15. The magnetoresistive element according to claim 14, further comprising the other diffusion preventing layer between the other second pinned magnetic layer and the other nonmagnetic coupling layer.
(Appendix 16)
The Mn-based Heusler alloy includes Co ₂ MnX (X is any one selected from the group consisting of Al, Ge, Si, Ga, In, Sb, and Sn), Ni ₂ MnAl, Ni ₂ MnSn, Cu ₂ MnAl, _{Pd 2 MnIn, Pd 2 MnSn,} Pd 2 MnSb, NiMnSb, PtMnSb, PdMnSb, and among the note 15, which is a one of the group consisting of PtMnSn, magnetic according to any one claim Resistive effect element.
(Appendix 17)
When the coordinates of each composition are expressed as (Co content, Fe content, Al content) in the ternary composition diagram, the CoFeAl is represented by points A (55, 10, 35) and B (50, 15). , 35), point C (50, 20, 30), point D (55, 25, 20), point E (60, 25, 15), point F (70, 15, 15), point A, point B , Point C, point D, point E, point F, and point A in this order, each having a composition within a straight line, the magnetoresistance according to any one of supplementary notes 1 to 16, Effect element (however, each content is expressed in atomic%).
(Appendix 18)
Any one of Supplementary notes 1 to 17, wherein the diffusion preventing layer, the other diffusion preventing layer, or the other diffusion preventing layer has a thickness set in a range of 0.5 nm to 2.0 nm. The magnetoresistive effect element according to one item.
(Appendix 19)
A magnetic head comprising the magnetoresistive element according to any one of appendices 1 to 18.
(Appendix 20)
A magnetic storage device comprising: a magnetic head having the magnetoresistive effect element according to any one of appendices 1 to 18, a recording element, and a magnetic recording medium.
(Appendix 21)
A CPP-type magnetoresistive film in which a fixed magnetic layer, a nonmagnetic metal layer, a diffusion prevention layer, and a free magnetic layer are stacked;
Writing means for applying a magnetic field to the magnetoresistive film to direct the magnetization of the free magnetic layer in a predetermined direction;
Read means for detecting a resistance value by supplying a sense current to the magnetoresistive film,
The free magnetic layer is made of a Mn-based Heusler alloy,
The magnetic memory device, wherein the diffusion prevention layer is made of CoFeAl.
(Appendix 22)
A CPP type magnetoresistive film in which a fixed magnetic layer, a nonmagnetic insulating layer, a free magnetic layer, another diffusion prevention layer, and a protective layer are laminated in this order;
Writing means for applying a magnetic field to the magnetoresistive film to direct the magnetization of the free magnetic layer in a predetermined direction;
Read means for detecting a resistance value by supplying a sense current to the magnetoresistive film,
The free magnetic layer is made of a Mn-based Heusler alloy,
2. The magnetic memory device according to claim 1, wherein the other diffusion prevention layer is made of CoFeAl.
(Appendix 23)
The Mn-based Heusler alloy includes Co ₂ MnX (X is any one selected from the group consisting of Al, Ge, Si, Ga, In, Sb, and Sn), Ni ₂ MnAl, Ni ₂ MnSn, Cu ₂ MnAl, _{Pd 2 MnIn, Pd 2 MnSn,} Pd 2 MnSb, NiMnSb, PtMnSb, PdMnSb, and magnetic memory device according to Supplementary note 20 or 21, wherein it is one of the group consisting of PtMnSn.
(Appendix 24)
When the coordinates of each composition are expressed as (Co content, Fe content, Al content) in the ternary composition diagram, the CoFeAl is represented by points A (55, 10, 35) and B (50, 15). , 35), point C (50, 20, 30), point D (55, 25, 20), point E (60, 25, 15), point F (70, 15, 15), point A, point B , Point C, point D, point E, point F, and point A, each having a composition in a region connected by a straight line in this order, the magnetic memory device according to any one of appendices 21 to 23 (However, each content is expressed in atomic%).
(Appendix 25)
The writing means applies a first magnetic field in one direction of the easy axis of the free magnetic layer substantially parallel to the film surface of the magnetoresistive film, and is substantially parallel to the film surface and the first magnetic field. 25. The magnetic memory device according to any one of appendices 21 to 24, wherein a second magnetic field is applied in a direction that forms a predetermined angle to control the direction of magnetization of the free magnetic layer.
(Appendix 26)
The writing means controls the magnetization direction of the free magnetic layer based on an electron current having a spin polarized in the magnetoresistive effect film. Magnetic memory device.
(Appendix 27)
A MOS transistor having a bit line, a word line, a control electrode and two current supply electrodes;
The word line is electrically connected to a control electrode;
The magnetoresistive film is electrically connected between the bit line and one current supply electrode,
The reading means sets a word line to a predetermined voltage, turns on a MOS transistor, and passes a sense current between the bit line and the one current supply electrode to detect a magnetoresistance value. The magnetic memory device according to appendix 24 or 25.

FIG. 3 is a diagram illustrating a main part of a medium facing surface of the magnetic head according to the first embodiment of the invention. It is sectional drawing of the GMR film | membrane of the 1st example which comprises the magnetoresistive effect element based on 1st Embodiment. It is sectional drawing of the GMR film | membrane of the 2nd example which comprises the magnetoresistive effect element based on 1st Embodiment. It is sectional drawing of the GMR film | membrane of the 3rd example which comprises the magnetoresistive effect element based on 1st Embodiment. It is sectional drawing of the GMR film | membrane of the 4th example which comprises the magnetoresistive effect element based on 1st Embodiment. It is sectional drawing of the GMR film | membrane of the 5th example which comprises the magnetoresistive effect element which concerns on 1st Embodiment. It is a diagram for explaining the degree of diffusion into the Cu film in CoFeAl film and Co ₂ MnGe film. It is a magnetic characteristic figure of a CoFeAl film and a CoFe film. It is a figure which shows the composition and coercive force of the free magnetic layer of the prototype example 4, a lower part, and an upper 2nd pinned magnetic layer. FIG. 6 is a relationship diagram between the coercive force and the composition of the CoFeAl film of Prototype Example 4. It is sectional drawing of the TMR film | membrane of the 1st example which comprises the magnetoresistive effect element which concerns on the 2nd Embodiment of this invention. It is sectional drawing of the TMR film | membrane of the 2nd example which comprises the magnetoresistive effect element which concerns on 2nd Embodiment. It is sectional drawing of the TMR film | membrane of the 3rd example which comprises the magnetoresistive effect element which concerns on 2nd Embodiment. It is sectional drawing of the TMR film | membrane of the 4th example which comprises the magnetoresistive effect element which concerns on 2nd Embodiment. It is a top view which shows the principal part of the magnetic memory device based on the 3rd Embodiment of this invention. (A) is sectional drawing of the magnetic memory device of the 1st example which concerns on the 4th Embodiment of this invention, (B) is a block diagram of the GMR film | membrane shown to (A). It is an equivalent circuit diagram of one memory cell of the magnetic memory device of the first example. It is a block diagram of the TMR film | membrane which comprises the modification of the magnetic memory device of a 1st example. It is sectional drawing of the magnetic memory device of the 2nd example which concerns on 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,108 Magnetic head 11 Ceramic substrate 12, 25 Alumina film 13 Inductive recording element 14 Upper magnetic pole 15 Recording gap layer 16 Lower magnetic pole 20 Magnetoresistive element 21 Lower electrode 22 Upper electrode 23 Insulating film 24 Magnetic domain control film 30, 50, 60, 70, 80 Magnetoresistive (GMR) film 31 Underlayer 32 Antiferromagnetic layer (lower antiferromagnetic layer)
33, 53, 81 Fixed magnetization stack (lower fixed magnetization stack)
34. First fixed magnetic layer (lower first fixed magnetic layer)
35 Nonmagnetic coupling layer (lower nonmagnetic coupling layer)
36, 56 Second pinned magnetic layer (lower second pinned magnetic layer)
37 Nonmagnetic metal layer (lower nonmagnetic metal layer)
37a Nonmagnetic insulating layer (lower nonmagnetic insulating layer)
38 Diffusion prevention layer (first diffusion prevention layer, lower (first) diffusion prevention layer)
39 Free magnetic layer 40 Protective layer 41 Third diffusion prevention layer 51, 73 Second diffusion prevention layer (lower second diffusion prevention layer)
62 Upper antiferromagnetic layer 63, 72, 82 Upper fixed magnetization stack 64 Upper first fixed magnetization layer 65 Upper nonmagnetic coupling layer 66, 76 Upper second fixed magnetization layer 67 Upper nonmagnetic metal layer 67a Upper nonmagnetic insulating layer 68 First Diffusion Prevention Layer (Upper (First) Diffusion Prevention Layer)
74 Upper second diffusion prevention layer 83 Lower interface magnetic layer 84 Upper interface magnetic layer 91-94 Tunnel magnetoresistance effect (TMR) film 100 Magnetic storage device 110, 130 Magnetic memory device 111 Memory cell 112 MOS type FET
118 Plate line 119 Word line for reading 120 Bit line 121 Word line for writing

Claims (5)

A CPP type magnetoresistive element,
A fixed magnetization layer, a nonmagnetic metal layer, a diffusion prevention layer, and a free magnetization layer are laminated in this order,
The free magnetic layer is made of a Mn-based Heusler alloy,
2. The magnetoresistive element according to claim 1, wherein the diffusion preventing layer is made of CoFeAl. A CPP type magnetoresistive element,
A fixed magnetic layer, a nonmagnetic insulating layer, a free magnetic layer, another diffusion prevention layer, and a protective layer are laminated in this order,
The protective layer is made of a nonmagnetic metal material,
The free magnetic layer is made of a Mn-based Heusler alloy,
The other diffusion preventing layer is made of CoFeAl.   When the coordinates of each composition are expressed as (Co content, Fe content, Al content) in the ternary composition diagram, the CoFeAl is represented by points A (55, 10, 35) and B (50, 15). , 35), point C (50, 20, 30), point D (55, 25, 20), point E (60, 25, 15), point F (70, 15, 15), point A, point B A magnetoresistive effect element according to claim 1 or 2, characterized in that it has a composition in a region where points C, D, E, F, and A are connected in a straight line in this order. The content is expressed in atomic%).   A magnetic storage device comprising: a magnetic head having the magnetoresistive effect element according to claim 1; a recording element; and a magnetic recording medium. A CPP-type magnetoresistive film in which a fixed magnetic layer, a nonmagnetic metal layer, a diffusion prevention layer, and a free magnetic layer are stacked;
Writing means for applying a magnetic field to the magnetoresistive film to direct the magnetization of the free magnetic layer in a predetermined direction;
Read means for detecting a resistance value by supplying a sense current to the magnetoresistive film,
The free magnetic layer is made of a Mn-based Heusler alloy,
The magnetic memory device, wherein the diffusion prevention layer is made of CoFeAl.

Images