JP2008108821A - Magnetoresistance effect element, laminate, wafer, head-gimbal assembly, hard disk device and manufacturing method for magnetoresistance effect element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a high magnetoresistance rate-of-change in a low RA region in a CPP-GMR type magnetoresistance effect element. <P>SOLUTION: The magnetoresistance effect element has a lower layer, an upper layer and a spacer layer held between the lower layer and the upper layer. The direction of a magnetization of one of the lower layer and the upper layer is fixed to an external magnetic field, and the direction of the magnetization of the other of the lower layer and the upper layer is changed in response to the external magnetic field. A sense current is made to flow through each layer of the lower layer, spacer layer and upper layer in the film-surface vertical direction. The spacer layer 8 has a first region 84 consisting of a first material having a relatively small electric resistance per a unit sectional area and a second region 85 consisting of a second material having a relatively large electric resistance per the unit sectional area in at least one cross section parallel with the film surface of the spacer layer 8. The second material mainly comprises a composition consisting of either of aluminum, silicon, chromium, titanium and hafnium and manganese and oxygen. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a magnetoresistive effect element, a laminate, a wafer, a head gimbal assembly, a hard disk device, and a method of manufacturing a magnetoresistive effect element, and in particular, a structure of a spacer layer of a current confinement type CPP-GMR element and the spacer layer The present invention relates to a method for manufacturing a CPP-GMR element having

  A spin valve type GMR (Giant Magneto-Resistive) head is known as a magnetic head that satisfies the requirements of a high sensitivity and high output head. A magnetic field detection element used for a spin valve type GMR element has a configuration in which a free layer and a pinned layer are stacked with a nonmagnetic spacer layer interposed therebetween. A free layer is a ferromagnetic material whose magnetization direction changes according to an external magnetic field. A pinned layer is a ferromagnetic material whose magnetization direction is fixed with respect to an external magnetic field. The magnetization direction of the free layer forms a relative angle corresponding to the external magnetic field with respect to the magnetization direction of the pinned layer, and the spin-dependent scattering of conduction electrons changes according to the relative angle, resulting in a change in magnetoresistance. The magnetic head detects the magnetic resistance change and reads the magnetic information on the recording medium.

  The pinned layer may be configured as a so-called synthetic pinned layer. The synthetic pinned layer includes an outer pinned layer whose magnetization direction is fixed with respect to an external magnetic field, an inner pinned layer provided closer to the spacer layer than the outer pinned layer, and an outer pinned layer and an inner pinned layer. A nonmagnetic intermediate layer sandwiched between the layers is provided. The magnetization direction of the inner pinned layer is firmly fixed by antiferromagnetic coupling with the outer pinned layer. Further, the magnetic moments of the outer pinned layer and the inner pinned layer cancel each other, and the leakage magnetic field as a whole is suppressed.

  Recently, a CPP (Current Perpendicular to the Plane) -GMR element in which a sense current flows in a direction perpendicular to the film surface has been studied as a magnetoresistive effect element that can be expected to have a higher output. In the CPP-GMR element, since the magnetic field detection element and the shield film are connected via a metal, there is an advantage that heat dissipation efficiency is improved and an operating current can be obtained. In the CPP-GMR element, the smaller the cross-sectional area of the element, the larger the resistance value, and the magnetoresistance change also increases. That is, there is an advantage that it is more suitable for narrowing the track width.

The magnetoresistance change increases as the spin polarizability of the free layer and the pinned layer increases. Therefore, if a material having a high spin polarizability is used for the free layer and the pinned layer, the magnetoresistance change rate increases accordingly, leading to an increase in output. A magnetic material having a spin polarizability of 100% or close thereto is called a half metal. A Heusler alloy is known as a material for realizing a half metal. In recent years, it has been proposed to use a Heusler alloy for a free layer and a pinned layer instead of the conventionally used CoFe alloy and NiFe alloy. For example, Patent Document 1 discloses a film configuration in which a Co ₂ MnGe (Heusler alloy) layer and a CoFe layer are provided as part of a pinned layer, and a Cu layer is formed thereon as a spacer layer.

In recent years, current confinement type CPP-GMR elements have been proposed as one means for improving the magnetoresistance change rate of CPP-GMR elements (Patent Documents 2 to 4). In the current confinement type CPP-GMR element, the spacer layer is provided with a conductive region having a low electrical resistance and an insulating region having a high electrical resistance. For this reason, the region through which the sense current flows is mainly limited to the conductive region, and an effect is obtained in which the cross-sectional area of the element is reduced in a pseudo manner. As a result, the amount of change in resistance is increased, and a high magnetoresistance change rate is obtained. Non-Patent Document 1 discloses an example of a current confinement type CPP-GMR element having a magnetoresistance change rate of 8.2% and an area resistance RA of 0.57 Ωμm ² . The area resistance RA is the product of the element resistance R and the cross-sectional area A of the element. Since a lower S / N ratio (Signal Noise Ratio) can be obtained with a lower RA, it is advantageous to reduce the RA for higher recording density. For example, when a magnetic head exceeding 300 Gbpsi is put into practical use, a low RA of 0.1 to 0.3 Ωμm ² is desired.
Japanese Patent Laid-Open No. 2005-19484 JP 2002-208744 A JP 2004-153248 A Japanese Patent Laid-Open No. 2003-8108 Fukuzawa Hideaki et al., “CPP-GMR spin valve film using CCP-NOL”, Journal of Japan Society of Applied Magnetics, 2005, Vol. 9, p. 869-877

One problem with the current confinement type CPP-GMR element is that the rate of change in magnetoresistance decreases in the low RA region. This is partly because the specific resistance of the spacer layer (Cu layer) contributing to the GMR effect increases due to the influence of oxygen. For example, Non-Patent Document 1 describes the relationship between RA and magnetoresistance change rate (Fig. ⁵ ), but in the low RA region (0.1 to 0.3 Ωμm ² ), the magnetoresistance change rate is 4 at most. It remains at ~ 5%. If the rate of change in magnetoresistance is small, it is difficult to obtain a high S / N ratio even if RA is kept small.

  In view of the above problems, an object of the present invention is to provide a CPP-GMR type magnetoresistive element capable of obtaining a high magnetoresistance change rate in a low RA region. Another object of the present invention is to provide a method for efficiently manufacturing such a magnetoresistive element.

  The magnetoresistive effect element of the present invention has a lower layer, an upper layer, and a spacer layer sandwiched between the lower layer and the upper layer. The magnetization direction of one of the lower layer and the upper layer is fixed with respect to the external magnetic field, and the magnetization direction of the other of the lower layer and the upper layer changes according to the external magnetic field, and the lower layer, the spacer layer, and the upper layer A sense current flows in the direction perpendicular to the film surface. The spacer layer has a first region made of a first material having a relatively small electric resistance per unit cross-sectional area and an electric resistance per unit cross-sectional area in at least one cross section parallel to the film surface of the spacer layer. A second region made of a relatively large second material, wherein the second material is a composition comprising any of aluminum, silicon, chromium, titanium, hafnium, manganese, and oxygen. The main component.

  The second material is formed by combining a metal such as aluminum and manganese with oxygen. By containing manganese that is easily bonded to oxygen in the second material, manganese captures oxygen in the oxidation treatment for forming the second material, and suppresses the influence of oxygen on the first material. it can. For this reason, the specific resistance of the first material is maintained at a small value, and the sense current easily flows. Therefore, it becomes easy to reduce the RA of the spacer layer and secure a large magnetoresistance change rate.

  The laminated body of this invention is equipped with said magnetoresistive effect element.

  The wafer of the present invention is formed with the magnetoresistive element described above.

  The head gimbal assembly of the present invention includes the above-described laminated body, and includes a slider disposed to face the recording medium and a suspension that elastically supports the slider.

  A hard disk device of the present invention includes the above-described laminated body, and includes a slider disposed to face a disk-shaped recording medium that is rotationally driven, and a positioning device that supports the slider and positions the recording medium. Have.

The magnetoresistive effect element manufacturing method of the present invention includes a lower layer, an upper layer, and a spacer layer sandwiched between the lower layer and the upper layer, and one of the lower layer and the upper layer is an external magnetic field. The magnetization direction of the lower layer and the upper layer changes according to the external magnetic field, and a sense current flows through the lower layer, the spacer layer, and the upper layer in the direction perpendicular to the film surface. This is a manufacturing method of the magnetoresistive effect element. The manufacturing method of the present invention includes a step of forming at least a part of a lower layer by laminating a Heusler alloy material layer and an iron / cobalt alloy layer in this order, and a spacer layer on the iron / cobalt alloy layer. Forming a conductive layer as a part of the substrate, laminating a raw material body made of any of aluminum, silicon, chromium, titanium, and hafnium on the conductive layer, and oxidizing at least a part of the raw material body; ,
Forming an upper layer on the oxidized source body, and forming a Heusler alloy layer from a Heusler alloy material layer by heating the lower layer, the spacer layer, and the upper layer, and comprising: The alloy material layer is composed of a composition of cobalt, manganese, and one or more elements selected from aluminum, silicon, gallium, antimony, and germanium.

  Another manufacturing method of the magnetoresistive effect element of the present invention includes a lower layer, an upper layer, and a spacer layer sandwiched between the lower layer and the upper layer, and one of the lower layer and the upper layer is The magnetization direction is fixed with respect to the external magnetic field, and the magnetization direction of the other of the lower layer and the upper layer changes according to the external magnetic field. It is a manufacturing method of the magnetoresistive effect element made to flow. In the manufacturing method of the present invention, at least a part of the lower layer is formed by laminating a Heusler alloy material layer made of a composition of cobalt, iron, and silicon and an iron-cobalt alloy layer in this order. And a step of forming a conductive layer as a part of the spacer layer on the iron / cobalt alloy layer, a raw material body made of any of aluminum, silicon, chromium, titanium, and hafnium and a manganese layer on the conductive layer Or at least one part of the raw material body and at least a part of the manganese layer are oxidized, and at least a part of the oxidized raw material body and the manganese layer are laminated. Forming an upper layer thereon.

  Instead of forming at least a part of the lower layer by laminating a Heusler alloy material layer and an iron / cobalt alloy layer in this order, the step of forming the lower layer by an iron / cobalt alloy layer is used. May be.

  As described above, according to the present invention, it is easy to reduce the RA of the spacer layer and ensure a large magnetoresistance change rate. Therefore, according to the present invention, it is possible to provide a CPP-GMR magnetoresistive element capable of obtaining a high magnetoresistance change rate in a low RA region. In addition, the present invention can provide a method for efficiently manufacturing such a magnetoresistive element.

  An embodiment of a thin film magnetic head using a magnetic field detection element of the present invention will be described with reference to the drawings. In the following embodiments, a thin film magnetic head for a hard disk device will be described. However, the magnetic field detection element of the present invention can also be applied to a magnetic memory element, a magnetic sensor assembly, and the like.

  (First Embodiment) FIG. 1 is a partial perspective view of a thin film magnetic head using a magnetoresistive element of the present invention. The thin film magnetic head 1 may be a read-only head or an MR / inductive composite head further having a recording unit. The magnetic field detection element 2 is a CPP-GMR element and is sandwiched between the upper electrode / shield 3 and the lower electrode / shield 4 and is disposed at a position where the leading end faces the recording medium 21. A sense current 22 can flow in the magnetic field detection element 2 in a direction perpendicular to the film surface by a voltage applied between the upper electrode / shield 3 and the lower electrode / shield 4. The magnetic field of the recording medium 21 on the surface facing the magnetic field detection element 2 changes as the recording medium 21 moves in the moving direction 23. The magnetic field detection element 2 can read the magnetic information written in each magnetic domain of the recording medium 21 by detecting the change in the magnetic field as a change in electric resistance by the GMR effect.

  FIG. 2 is a side view of the magnetic field detection element as viewed from the AA direction in FIG. 1, that is, from the medium facing surface. Here, the medium facing surface is a surface facing the recording medium 21 of the thin film magnetic head 1. Table 1 shows an example of the film configuration of the magnetic field detection element 2 of the present invention. Table 1 shows the buffer layer 5 in contact with the lower electrode / shield 4 and the cap layer 10 in contact with the upper electrode / shield 3 in the order of lamination from the bottom to the top. In the text and tables, the description such as Co70Fe30 means the atomic fraction of each element (the numerical unit is%). For example, Co70Fe30 means that the atomic fraction of Co is 70% and the atomic fraction of Fe is 30%. However, other trace elements may be added within a range in which equivalent magnetic properties can be obtained, and each layer does not need to be composed of only the elements described in a strict sense. In the text and tables, x in the description of (Al + Mn) Ox or the like means an arbitrary integer.

The magnetic field detecting element 2 includes a buffer layer 5 made of a Ta / Ru layer, an antiferromagnetic layer 6 made of an IrMn layer, a pinned layer 7 and Cu on a lower electrode / shield 4 made of a NiFe layer having a thickness of about 1 μm. This is a laminate in which a spacer layer 8, a free layer 9, and a cap layer 10 are laminated in this order. The pinned layer 7 is a layer whose magnetization direction is fixed with respect to an external magnetic field. The free layer 9 is a layer whose magnetization direction changes according to an external magnetic field. In this specification, the notation generally indicated by A1 /../ An means a stacked body in which the layers A1 to An are stacked in this order. The film configuration of the buffer layer 5 is selected so that exchange coupling with the antiferromagnetic layer 6 is good. The cap layer 10 is made of a Ru layer, and is provided for preventing deterioration of each laminated layer. An upper electrode / shield 3 made of a NiFe film having a thickness of about 1 μm is formed on the cap layer 10. A hard bias film 12 is formed on the side of the magnetic field detection element 2 via an insulating film 11. The hard bias film 12 is a magnetic domain control film for converting the magnetic domain of the free layer 9 into a single magnetic domain. The insulating film 11 is made of Al ₂ O ₃ , and the hard bias film 12 is made of CoPt, CoCrPt, or the like.

  FIG. 3 is a diagram showing the main part of the magnetic field detection element, specifically showing the film configuration of the pinned layer 7, the spacer layer 8, and the free layer 9 conceptually. The pinned layer 7 uses a so-called synthetic pinned layer. That is, the pinned layer 7 is sandwiched between the outer pinned layer 71, the inner pinned layer 73 provided closer to the spacer layer 8 than the outer pinned layer 71, and the outer pinned layer 71 and the inner pinned layer 73. And a non-magnetic intermediate layer 72. In the synthetic pinned layer, the outer pinned layer 71 and the inner pinned layer 73 are antiferromagnetically coupled by the nonmagnetic intermediate layer 72, and the magnetization direction of the inner pinned layer 73 is firmly fixed. At the same time, the effective magnetization of the pinned layer 7 is suppressed and a stable magnetization state can be maintained.

  The outer pinned layer 71 is made of, for example, Co70Fe30 in order to ensure the exchange coupling strength with the antiferromagnetic layer 6. The nonmagnetic intermediate layer 72 is made of Ru in order to ensure antiferromagnetic coupling between the outer pinned layer 71 and the inner pinned layer 73.

The inner pinned layer 73 is composed of a laminate of an FeCo layer 731 / Heusler alloy layer 732 / FeCo layer 733. The FeCo layer 733 is sandwiched between the Heusler alloy layer 732 and the spacer layer 8. The Heusler alloy layer 732 is made of Co ₂ MnGe or Co ₂ MnSi, but is not limited thereto, and the composition formula is Co ₂ MnZ (where Z is selected from Al, Si, Ga, Sb, and Ge). 1 type or 2 or more types of elements). The film thickness of the Heusler alloy layer 732 can be appropriately selected within a range of 0.1 to 0.4 nm. As will be described later, the FeCo layer 733 is set to an appropriate film thickness so that Mn in the Heusler alloy material layer 732a that is the origin of the Heusler alloy layer 732 can easily diffuse and move toward the spacer layer 8. Details will be described in Examples.

  The spacer layer 8 is an interface between a first conductive layer 81 made of Cu (first material) and a second conductive layer 82 made of Cu similarly to the first conductive layer 81 and the first conductive layer 81, 82. And an insulator 83 made of an insulating material (second material) formed in the vicinity of 86. The insulator 83 is formed in a sea-island shape on the interface 86, and the interface 86 has a first region 84 having a relatively small electrical resistance per unit cross-sectional area and a second region having a relatively large electrical resistance per unit cross-sectional area. The area 85 is divided. The sense current 22 is blocked in the second region 85 and mainly passes through the first region 84. This causes a current confinement effect and increases the magnetoresistance change rate. The spacer layer 8 can take any configuration as long as such a current confinement effect can be realized. Therefore, the insulator 83 may be provided for a part of the thickness of the spacer layer 8 as shown in FIG. 3, but penetrates the spacer layer 8 over the entire thickness of the spacer layer 8. It may be provided as follows. In other words, the first and second regions 84 and 85 may be formed in at least one cross section parallel to the film surface of the spacer layer 8.

The insulator 83 is mainly composed of a composition of aluminum, manganese, and oxygen. Any of silicon, chromium, titanium, and hafnium may be used instead of aluminum. The composition may be a state in which AlO _x and MnO _x are mixed, or may be in a state in which aluminum and manganese are combined with oxygen in an amorphous state. What is important is that manganese is not contained in the first conductive layer 81, and that the first conductive layer 81 is made of high-purity copper. This point will be described again in the description of the method of manufacturing a magnetoresistive element (described later).

When the Heusler alloy layer 732 of the pinned layer 7 is made of Co ₂ MnGe and the second material is made of aluminum, the ratio of the atomic fraction of manganese to the total atomic fraction of aluminum and manganese in the spacer layer 8 is It is desirable to be in the range of 6% or more and 59% or less. At this time, the film thickness of the FeCo layer 733 is in the range of 0.3 nm to 1.9 nm.

When the Heusler alloy layer 732 of the pinned layer 7 is formed of Co ₂ MnSi and the second material is made of aluminum, the ratio of the atomic fraction of manganese to the total atomic fraction of aluminum and manganese in the spacer layer 8 is It is desirable to be in the range of 10% or more and 54% or less. At this time, the film thickness of the FeCo layer 733 is in the range of 0.4 nm to 1.7 nm.

  The free layer 9 has a CoFe layer 91 and a NiFe layer 92. The CoFe layer 91 preferably has a body centered cubic (bcc) structure. The NiFe layer 92 mainly shares the soft magnetic characteristics of the free layer 9, and the CoFe layer 91 is inserted to improve the magnetoresistance change rate.

Next, a method for manufacturing the above-described thin film magnetic head will be described with reference to FIG. First, as shown in FIG. 2, a lower electrode / shield is formed on a substrate (not shown) made of a ceramic material such as AlTiC (Al ₂ O ₃ .TiC) via an insulating layer (not shown). 4 is formed. Subsequently, as shown in FIG. 2 and FIG. 4A, the layers from the buffer layer 5 to the pinned layer 7 are sequentially formed by sputtering. Further, as shown in FIG. 4A, a conductive layer 81 made of copper is formed on the FeCo layer 733 as a part of the spacer layer 8. The Heusler alloy material layer 732a forming the pinned layer 7 is made of a Heusler alloy material whose composition formula is represented by Co ₂ MnGe, but is not ordered at this point. The composition formula of the Heusler alloy material layer 732a can be generally expressed as Co ₂ MnZ (Z is one or more elements selected from Al, Si, Ga, Sb, and Ge). However, as will be described later, it is preferable that the atomic fraction of manganese is larger than the stoichiometric composition of the Heusler alloy.

  Next, as shown in FIG. 4B, a raw material body 87 made of aluminum is laminated on the conductive layer 81. The raw material body 87 is a layer that is a material of the insulator 83, and silicon, chromium, titanium, or hafnium may be used depending on the components of the insulator 83. The raw material body 87 can use a general film forming process such as a sputtering method as with the other layers. Although the film thickness of the raw material body 87 is about 0.1 to 0.4 nm, this film thickness is a mass film thickness obtained from the film formation rate, and the raw material body 87 is not actually a complete continuous film. It is thought that it is formed in a shape. As a result, as shown in FIG. 4B, both the aluminum that is the material of the raw material body 87 and the copper that is the material of the conductive layer 81 are exposed on the surface (interface 86) of the raw material body 87. it is conceivable that.

Next, as shown in FIG. 4C, at least a part of the raw material body 87 is oxidized. This step is an important step for forming the insulator 83 in the spacer layer 8 in the current confinement type CPP-GMR element. Oxidation can be done either by oxygen exposure or plasma oxidation. In the case of oxygen exposure, it is desirable to expose at about 0.67 mPa (0.005 mTorr) to 133 mPa (1.000 mTorr) for about 1 to 200 seconds. In the case of plasma oxidation, it is desirable to expose in an argon + O ₂ atmosphere for about 1 to 60 seconds.

When the raw material body 87 is placed in an oxygen atmosphere, Mn atoms in the Heusler alloy material layer 732a diffuse and move, pass through the FeCo layer 733 and the conductive layer 81, and reach the surface of the conductive layer 81. As a result, manganese is exposed in the oxygen atmosphere in addition to aluminum and copper. Aluminum has the largest bonding strength with oxygen of these three kinds of metals, followed by manganese, and the weakest is copper. For this reason, oxygen is combined (oxidized) with aluminum and manganese, and the oxidized manganese is incorporated as a part of the insulator 83. However, since copper hardly binds to oxygen, the conductive layer 81 remains almost as deposited even after the oxidation process, and the copper is maintained in high purity. That is, copper oxidation is prevented by the manganese diffused from the Heusler alloy material layer 732a. The oxides of aluminum and manganese may coexist in the form of individual oxides (AlO _x and MnO _x ), and aluminum and manganese may exist together in an oxide state. In either case, manganese concentrates on the raw material body 87 in which aluminum was present, and after the oxidation process, an oxide of aluminum and manganese (insulator 83) is formed in a sea island state on the surface. Conceivable.

  Next, as shown in FIG. 4D, a conductive layer 82 made of copper is formed as a part of the spacer layer 8 on the oxidized raw material body 87, that is, the insulator 83. However, this step may be omitted, and the free layer 9 may be formed directly on the insulator 83.

  Next, the free layer 9 is formed on the conductive layer 82, and the cap layer 10 is further deposited thereon. Then, the ordered Heusler alloy layer 732 is formed from the Heusler alloy material layer 732a by heating the substrate on which the cap layer 10 is deposited.

  Further, each layer from the buffer layer 5 to the cap layer 10 is patterned into a predetermined shape to form the insulating film 11 and the hard bias film 12. Thereafter, as shown in FIG. 2, the upper electrode / shield 3 is formed, and the reading portion of the thin film magnetic head is completed. When a write element is provided, a write pole layer and a coil are further laminated. Thereafter, the whole is covered with a protective film, the wafer is cut, lapped, and separated into a laminate (slider) on which a thin film magnetic head is formed.

  In this way, by using the Heusler alloy material layer 732a containing manganese in the pinned layer 7 and diffusing manganese toward the raw material body 87, it becomes possible to form a stable oxide at the interface 86 of the spacer layer 8, and Cu The effect of oxygen on oxygen (increase in specific resistance) is suppressed. As a result, a large magnetoresistance change rate can be realized. As will be described in detail in the examples, it is more effective to shift the composition of the Heusler alloy material layer 732a to the manganese rich side by several percent in consideration of the movement of manganese in advance. A similar insulator 83 is formed even if manganese is added to the spacer layer 8 in advance.

  (Example) Next, in the method of manufacturing a thin film magnetic head described above, the following tests were conducted in order to obtain the optimum film thickness of the FeCo layer and the optimum atomic fraction of manganese in the Heusler alloy material layer.

Example 1 First, using the laminate having the film configuration shown in Table 2, the magnetoresistance change rate and RA were evaluated using the film thickness of the FeCo layer 733 as a parameter. This test was performed to estimate the film thickness of the FeCo layer 733 that is suitable for manganese to diffuse into the raw material body 87 through the FeCo layer 733. Co ₂ MnGe was used as the Heusler alloy material layer 732a, and the thickness of the FeCo layer 733 was changed from 0 nm (without the FeCo layer 733) to 2 nm. The atomic fraction of Co ₂ MnGe was stoichiometric, ie 2: 1: 1. The junction size was 0.2 μm × 0.2 μm, and annealing was performed at 270 ° C. for 3 hours. The raw material was oxidized by exposure to oxidation. Comparative Example 1 shown in Table 3 is an example of a film configuration in which a Co70Fe30 layer is used instead of the Co ₂ MnGe layer in Table 2, and no manganese is present in the inner pinned layer. In Comparative Example 2, Co ₂ MnGe is used as the Heusler alloy material layer 732a, but no oxidation treatment is performed, and no diffusion of manganese occurs. That is, in any of the comparative examples, the insulator does not contain manganese, or even if it contains a very small amount. The results are shown in Table 3 and FIGS. In the following chart, the magnetoresistance change rate is abbreviated as MR ratio.

  Sample No. As shown in 1-1, if there is no FeCo layer 733, the amount of movement of manganese becomes excessive (see the column of “Al / Mn ratio in spacer layer” in Table 3). As a result, the atomic fraction of manganese in the Heusler alloy material layer 732a decreases, deviates from the stoichiometric composition of the Heusler alloy, and the ordering of the Heusler alloy does not progress. Therefore, it is considered that the polarizability of the Heusler alloy layer 732 is lowered and the magnetoresistance change rate is also reduced. As the film thickness of the FeCo layer 733 is increased, the amount of movement of manganese is suppressed and the ordering of the Heusler alloy is facilitated, so that the polarizability of the Heusler alloy layer 732 increases and the magnetoresistance change rate also increases. . However, when the film thickness of the FeCo layer 733 is too large, the amount of movement of manganese decreases and the influence of oxygen on Cu increases. For this reason, although the crystallization of the Heusler alloy layer 732 is performed well, the specific resistance of the Cu layer increases, the high polarizability cannot be utilized, and the magnetoresistance change rate decreases. In Comparative Examples 1 and 2, the magnetoresistance change rate is 4.5 to 5.1. If the lower limit value of the magnetoresistance change rate at which the effect of the present invention is obtained is about 6.0 with a margin, the FeCo layer It is preferable that the film thickness of 733 be in the range of 0.3 nm to 1.9 nm. At this time, in the spacer layer 8, the ratio of the atomic fraction of manganese to the total atomic fraction of aluminum and manganese is in the range of 6% to 59% as shown in FIG. In other words, when the ratio of the atomic fraction of manganese to the sum of the atomic fractions of aluminum and manganese is within this range, the effect of suppressing the influence of oxygen on the crystallization of Heusler alloy layer 732 is balanced. Thus, a good magnetoresistance change rate can be obtained.

  FIG. 7 is a map of element distribution from the pinned layer to the free layer, created using secondary ion mass spectrometry (SIMS). The horizontal axis is time. The figure shows the milling time and the position of each layer determined from the detected elements. FIG. 4A shows the distribution of the main elements when the oxidation treatment is not performed, and FIG. 4B shows the distribution of the main elements when the oxidation treatment is performed. When oxidation treatment is not performed, manganese is concentrated in the pinned layer 7 and the antiferromagnetic layer 6 as shown in FIG. 7A, and the amount of manganese distribution in the spacer layer is small. On the other hand, when the oxidation treatment is performed, the distribution amount of manganese in the spacer layer increases as shown in FIG. 7B. Thus, it was confirmed from the mass spectrometry result by SIMS that manganese was diffused and transferred by the oxidation treatment.

(Example 2) In the same manner as in Example 1, the magnetoresistive change rate and RA were evaluated using the laminate having the film structure shown in Table 4 and the film thickness of the FeCo layer 733 as a parameter. The purpose of the test is the same as in Example 1. Co ₂ MnSi was used as the Heusler alloy material layer 732a, and the thickness of the FeCo layer 733 was changed from 0 nm (without the FeCo layer 733) to 2 nm. The atomic fraction of Co ₂ MnSi was stoichiometric, ie 2: 1: 1. As a comparative example, in addition to the comparative example 1, the comparative example 3 using Co ₂ FeSi as the Heusler alloy material layer 732a was used. As a result, in any of the comparative examples, the insulator 83 does not contain manganese. Other test conditions are the same as in Example 1. The results are shown in Table 5 and FIGS.

  Similar to Example 1, when there is no FeCo layer 733 and when the thickness of the FeCo layer 733 is small, the amount of movement of manganese becomes excessive, and the magnetoresistance change rate decreases for the same reason as in Example 1. On the other hand, when the film thickness of the FeCo layer 733 is large, the influence of oxygen on Cu increases, and the magnetoresistance change rate decreases. When the lower limit value of the magnetoresistance change rate at which the effect of the present invention is obtained is about 6.0 like Example 1, the film thickness of the FeCo layer is in the range of 0.4 nm to 1.7 nm. It is desirable to form. At this time, as shown in FIG. 6, in the spacer layer 8, the ratio of the atomic fraction of manganese to the sum of the atomic fractions of aluminum and manganese is in the range of 10% to 54%.

  (Example 3) In the film configuration of Example 1, the atomic fraction of manganese in the Heusler alloy material layer 732a was previously set larger than the stoichiometric composition, and the magnetoresistance change rate and RA were similarly evaluated. In this test, in consideration of the diffusion of manganese, a large amount of manganese is previously contained in the Heusler alloy material layer 732a, so that the manganese has a stoichiometric composition in the Heusler alloy material layer 732a after the manganese has diffused. It was carried out because it was thought that the Heusler alloy was well ordered by the subsequent annealing treatment with a close composition. The test conditions were the same as in Example 1, and the thickness of the FeCo layer 733 was 1.0 nm. That is, the sample Nos. The atomic fraction of manganese was changed with respect to 1-5. The results are shown in Table 6.

  From this, it was confirmed that the magnetoresistive change rate is increased by including manganese in the Heusler alloy material layer 732a in advance in a larger amount than 25% of the stoichiometric composition of the Heusler alloy. The reason for this is that, as described above, manganese remains in the Heusler alloy material layer 732a after the manganese has diffused in a composition close to the stoichiometric composition, and the Heusler alloy is well ordered. This is probably because the polarizability of the alloy layer increased.

  (Example 4) In the film configuration of Example 2, similarly to Example 3, the atomic fraction of manganese in the Heusler alloy material layer 732a was previously set larger than the stoichiometric composition of Heusler alloy, and similarly Magnetoresistance change rate and RA were evaluated. The test conditions were the same as in Example 2, and the thickness of the FeCo layer 733 was 1.0 nm. That is, the sample Nos. The atomic fraction of manganese was changed with respect to 2-5. The results are shown in Table 7.

  As in Example 3, it was confirmed that the magnetoresistance change rate was increased by adding more than 25% of the stoichiometric composition of manganese to the Heusler alloy material layer in advance. The reason is considered to be the same as in Example 3.

  (Example 5) In the film configuration of Example 1, instead of including manganese in the Heusler alloy material layer, it was formed directly on the conductive layer 81, and the influence on the magnetoresistance change rate was evaluated. An FeCo layer was provided instead of the Heusler alloy layer as a ferromagnetic layer of the pinned layer, and the raw material body 87 (second material) was formed of a composition composed of aluminum and manganese. Manganese is deposited on the conductive layer 81 simultaneously with aluminum, but either can be deposited first. By using the film thickness of the FeCo layer 733 as a parameter, the atomic fraction of manganese with respect to aluminum in the spacer layer 8 was changed, and the influence on the magnetoresistance change rate was examined. The test conditions are the same as in Example 1. The results are shown in Table 8. The magnetoresistance change rate also tended to increase by forming manganese directly on the conductive layer 81. This is presumably because a composition comprising manganese, aluminum, and oxygen was formed in the spacer layer 8 to prevent the influence of oxygen on the Cu layer. When the ratio of the atomic fraction of manganese to the total atomic fraction of aluminum and manganese was in the range of 43% to 56%, the effect of increasing the magnetoresistance change rate was confirmed.

(Embodiment 6) Further, in the film configuration of Embodiment 1, the Heusler alloy material layer 732a of the pinned layer 7 is formed of Co ₂ FeSi not containing manganese, and manganese is simultaneously conductive with aluminum as in Embodiment 5. It was deposited on 81 and the influence on the magnetoresistance change rate was evaluated. The raw material body 87 (second material) was formed of a composition composed of aluminum and manganese. By using the film thickness of the FeCo layer as a parameter, the atomic fraction of manganese with respect to aluminum in the spacer layer 7 was changed, and the influence on the magnetoresistance change rate was examined. The test conditions are the same as in Example 1. The results are shown in Table 9. As in Example 5, the magnetoresistance change rate tended to increase by forming manganese directly on the conductive layer 81. The reason is considered to be the same as in Example 5. Also in this case, the effect of increasing the magnetoresistance change rate was confirmed when the ratio of the atomic fraction of manganese to the total atomic fraction of aluminum and manganese was 43% or more and 56% or less.

In the embodiments and examples described above, the magnetic field detection element 2 is a bottom spin type in which the pinned layer 7 is a lower layer with respect to the spacer layer 8 and the free layer 9 is an upper layer with respect to the spacer layer 8. However, a top spin type in which the pinned layer becomes the upper layer and the free layer becomes the lower layer may be used. Table 10 shows an example of the film structure of the top spin type. The table corresponds to Table 1, and the film configuration from the free layer to the antiferromagnet is opposite to Table 1. In the table, Z represents any of aluminum, silicon, chromium, titanium, and hafnium. Further, in order to create the magnetic field detection element shown in Table 10, it is desirable to use an alloy containing manganese as the Heusler alloy material layer of the free layer, and Co ₂ MnSi can be used in addition to Co ₂ MnGe. Furthermore, as shown in Examples 5 and 6, manganese can be deposited on the conductive layer together with aluminum.

  Next, a wafer used for manufacturing the above-described thin film magnetic head will be described. FIG. 8 is a conceptual plan view of the wafer. The wafer 100 includes a plurality of magnetoresistive elements 1 in which at least the lower electrode 3 to the upper electrode 4 are stacked. By cutting the wafer 100, the magnetoresistive effect element 1 is divided into a plurality of bars 101 arranged in a line. The bar 101 is a unit of work when the medium facing surface ABS is polished. The bar 101 is further cut after polishing and separated into a slider including a thin film magnetic head. The wafer 100 is provided with a cutting margin (not shown) for cutting the bar 101 and the slider.

  Next, a head gimbal assembly and a hard disk device using a thin film magnetic head will be described. First, the slider 210 included in the head gimbal assembly will be described with reference to FIG. The slider 210 is a laminated body that is disposed in the hard disk device so as to face a hard disk that is a disk-shaped recording medium that is rotationally driven. The slider 210 has a substantially hexahedron shape, and one surface thereof is a medium facing surface ABS facing the hard disk. When the hard disk rotates in the z direction in FIG. 9, lift is generated in the slider 210 downward in the y direction by an air flow passing between the hard disk and the slider 210. The slider 210 floats from the surface of the hard disk by this lifting force. Near the end of the slider 210 on the air outflow side (lower left end in FIG. 9), the thin film magnetic head 1 of the present invention is formed.

  Next, a head gimbal assembly 220 including a thin film magnetic head will be described with reference to FIG. The head gimbal assembly 220 includes a slider 210 and a suspension 221 that elastically supports the slider 210. The suspension 221 includes, for example, a leaf spring-like load beam 222 formed of stainless steel, a flexure 223 that is provided at one end of the load beam 222 and is joined to the slider 210 to give the slider 210 an appropriate degree of freedom. And a base plate 224 provided at the other end of the beam 222. A portion of the flexure 223 to which the slider 210 is attached is provided with a gimbal portion for keeping the posture of the slider 210 constant.

  The head gimbal assembly 220 attached to one arm 230 is called a head arm assembly. The arm 230 moves the slider 210 in the track crossing direction x of the hard disk 262. One end of the arm 230 is attached to the base plate 224. A coil 231 that is a part of the voice coil motor is attached to the other end of the arm 230. A bearing portion 233 to which a shaft 234 that rotatably supports the arm 230 is attached is provided at an intermediate portion of the arm 230. The arm 230 and the voice coil motor that drives the arm 230 constitute an actuator.

  Next, a head stack assembly and a hard disk drive using a thin film magnetic head as a head element will be described with reference to FIGS. The head stack assembly is a head gimbal assembly 220 attached to each arm of a carriage having a plurality of arms. FIG. 11 is an explanatory view showing a main part of the hard disk device, and FIG. 12 is a plan view of the hard disk device. The head stack assembly 250 has a carriage 251 having a plurality of arms 252. A head gimbal assembly 220 is attached to each arm 252 so as to be aligned in the vertical direction at intervals. A coil 253 that is a part of the voice coil motor is attached to the carriage 251 on the opposite side of the arm 252. The voice coil motor has permanent magnets 263 arranged at positions facing each other with the coil 253 interposed therebetween.

  Referring to FIG. 12, the head stack assembly 250 is incorporated in a hard disk device. The hard disk device has a plurality of hard disks 262 attached to a spindle motor 261. For each hard disk 262, two sliders 210 are arranged so as to face each other with the hard disk 262 interposed therebetween. The head stack assembly 250 and the actuator excluding the slider 210 correspond to the positioning device in the present invention, and support the slider 210 and position the slider 210 with respect to the hard disk 262. The slider 210 is moved by the actuator in the track crossing direction of the hard disk 262 and positioned with respect to the hard disk 262. The thin film magnetic head 1 included in the slider 210 records information on the hard disk 262 by the recording head, and reproduces information recorded on the hard disk 262 by the reproducing head.

It is a fragmentary perspective view of the thin film magnetic head using the magnetoresistive element of this invention. FIG. 2 is a side view of the magnetic field detection element as viewed from the AA direction in FIG. 1. FIG. 2 is a partial detail view showing a film configuration from a pinned layer to a free layer of the thin film magnetic head shown in FIG. 1. It is a flowchart which shows the manufacturing method of the magnetoresistive element of this invention. It is a graph which shows the relationship between the FeCo layer film thickness and magnetoresistive change rate in Example 1,2. It is a graph which shows the relationship between the atomic fraction of Co and magnetoresistive change rate in Example 1,2. It is a graph which shows the mass spectrometry result by SIMS. It is a top view of the wafer which concerns on manufacture of the laminated body of this invention. It is a perspective view which shows the slider contained in the head gimbal assembly incorporating the laminated body of this invention. It is a perspective view which shows the head arm assembly containing the head gimbal assembly incorporating the laminated body of this invention. It is explanatory drawing which shows the principal part of the hard-disk apparatus incorporating the laminated body of this invention. It is a top view of the hard disk drive incorporating the laminated body of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thin film magnetic head 2 Magnetic field detection element 3 Upper electrode and shield 4 Lower electrode and shield 5 Buffer layer 6 Antiferromagnetic layer 7 Pinned layer 71 Outer pinned layer 72 Nonmagnetic intermediate layer 73 Inner pinned layer 731 FeCo layer 732 Heusler alloy layer 732a Heusler alloy material layer 733 FeCo layer 8 spacer layer 81 first conductive layer 82 second conductive layer 83 insulator 84 first region 85 second region 86 interface 87 raw material 9 free layer 91 CoFe layer 92 NiFe layer 10 Cap layer 11 Insulating film 12 Hard bias film 21 Recording medium 22 Sense current

Claims (21)

A lower layer, an upper layer, and a spacer layer sandwiched between the lower layer and the upper layer,
One of the lower layer and the upper layer has a magnetization direction fixed to an external magnetic field,
The other of the lower layer and the upper layer changes its magnetization direction according to the external magnetic field,
A sense current flows through each of the lower layer, the spacer layer, and the upper layer in a direction perpendicular to the film surface,
The spacer layer includes, in at least one cross section parallel to the film surface of the spacer layer, a first region made of a first material having a relatively small electric resistance per unit cross section, and an electric power per unit cross section. A second region made of a second material having a relatively high resistance,
The second material is mainly composed of a composition comprising any of aluminum, silicon, chromium, titanium, hafnium, manganese, and oxygen.
Magnetoresistive effect element. The lower layer includes a Heusler alloy layer represented by a composition formula of Co ₂ MnZ (where Z is one or more elements selected from Al, Si, Ga, Sb, and Ge), An iron-cobalt alloy layer sandwiched between a Heusler alloy layer and the spacer layer;
The magnetoresistive effect element according to claim 1, wherein the second material is mainly composed of a composition comprising aluminum, manganese, and oxygen. The lower layer has a Heusler alloy layer whose composition formula is represented by Co ₂ MnGe,
The second material is mainly composed of a composition comprising aluminum, manganese and oxygen,
In the spacer layer, the ratio of the atomic fraction of manganese to the total atomic fraction of aluminum and manganese is in the range of 6% to 59%.
The magnetoresistive effect element according to claim 2. The lower layer has a Heusler alloy layer whose composition formula is represented by Co ₂ MnGe,
The second material is mainly composed of a composition comprising aluminum, manganese and oxygen,
The film thickness of the iron-cobalt alloy layer is in the range of 0.3 nm or more and 1.9 nm or less.
The magnetoresistive effect element according to claim 2. The lower layer has a Heusler alloy layer whose composition formula is represented by Co ₂ MnSi,
The second material is mainly composed of a composition comprising aluminum, manganese and oxygen,
In the spacer layer, the ratio of the atomic fraction of manganese to the total atomic fraction of aluminum and manganese is in the range of 10% or more and 54% or less.
The magnetoresistive effect element according to claim 2. The lower layer has a Heusler alloy layer whose composition formula is represented by Co ₂ MnSi,
The second material is mainly composed of a composition comprising aluminum, manganese and oxygen,
The film thickness of the iron-cobalt alloy layer is in the range of not less than 0.4 nm and not more than 1.7 nm.
The magnetoresistive effect element according to claim 2. The lower layer has a Heusler alloy layer whose composition formula is represented by Co ₂ FeSi, and an iron-cobalt alloy layer sandwiched between the Heusler alloy layer and the spacer layer,
The second material is mainly composed of a composition comprising aluminum, manganese, and oxygen,
In the spacer layer, the ratio of the atomic fraction of manganese to the total atomic fraction of aluminum and manganese is in the range of 43% or more and 56% or less.
The magnetoresistive effect element according to claim 1. The lower layer has an iron-cobalt alloy layer provided in contact with the spacer layer,
The second material is mainly composed of a composition comprising aluminum, manganese, and oxygen,
In the spacer layer, the ratio of the atomic fraction of manganese to the total atomic fraction of aluminum and manganese is in the range of 43% or more and 56% or less.
The magnetoresistive effect element according to claim 1.   The laminated body provided with the magnetoresistive effect element of any one of Claim 1 to 8.   A wafer on which the magnetoresistive effect element according to claim 1 is formed. A slider including the laminate according to claim 9 and disposed to face the recording medium;
A suspension for elastically supporting the slider;
A head gimbal assembly. A slider including the laminate according to claim 9 and disposed to face a disk-shaped recording medium that is rotationally driven;
A positioning device that supports the slider and positions the slider relative to the recording medium;
A hard disk device. A lower layer, an upper layer, and a spacer layer sandwiched between the lower layer and the upper layer, and one of the lower layer and the upper layer has a magnetization direction fixed to an external magnetic field. The other of the lower layer and the upper layer changes its magnetization direction in response to the external magnetic field, and a sense current flows through each of the lower layer, the spacer layer, and the upper layer in a direction perpendicular to the film surface. A method of manufacturing a magnetoresistive element,
Forming at least a part of the lower layer by laminating a Heusler alloy material layer and an iron-cobalt alloy layer in this order;
Forming a conductive layer on the iron-cobalt alloy layer as part of the spacer layer;
Laminating a raw material body made of any of aluminum, silicon, chromium, titanium, and hafnium on the conductive layer;
Oxidizing at least a portion of the raw material body;
Forming the upper layer on the oxidized raw material body;
Forming a Heusler alloy layer from a Heusler alloy material layer by heating the lower layer, the spacer layer, and the upper layer;
Have
The Heusler alloy material layer is composed of a composition of cobalt, manganese, and one or more elements selected from aluminum, silicon, gallium, antimony, and germanium.
Manufacturing method of magnetoresistive effect element.   In the oxidizing step, a part of manganese contained in the Heusler alloy layer is moved to the raw material body, and a composition comprising aluminum, silicon, chromium, titanium, or hafnium, manganese, and oxygen is included. The method of manufacturing a magnetoresistive effect element according to claim 13, comprising forming a sea island shape on the conductive layer.   15. The method of manufacturing a magnetoresistive effect element according to claim 13, wherein the oxidizing step is performed by oxygen exposure or plasma oxidation.   16. The method of forming a conductive layer made of the same material as the conductive layer as a part of the spacer layer on the oxidized raw material body before the step of forming the upper layer. The manufacturing method of the magnetoresistive effect element of any one of these.   The method of manufacturing a magnetoresistive effect element according to any one of claims 13 to 16, wherein the Heusler alloy material layer contains manganese in an atomic fraction higher than a stoichiometric composition of the Heusler alloy. The Heusler alloy material layer is composed of a composition of cobalt, manganese, and germanium,
The iron-cobalt alloy layer is formed so that the film thickness is in the range of 0.3 nm or more and 1.9 nm or less.
The method for manufacturing a magnetoresistive element according to claim 13. The Heusler alloy material layer is composed of a composition of cobalt, manganese, and silicon,
The iron-cobalt alloy layer is formed so that the film thickness is in the range of 0.4 nm to 1.7 nm.
The method for manufacturing a magnetoresistive element according to claim 13. A lower layer, an upper layer, and a spacer layer sandwiched between the lower layer and the upper layer, and one of the lower layer and the upper layer has a magnetization direction fixed to an external magnetic field. The other of the lower layer and the upper layer changes its magnetization direction in response to the external magnetic field, and a sense current flows through each of the lower layer, the spacer layer, and the upper layer in a direction perpendicular to the film surface. A method of manufacturing a magnetoresistive element,
Forming at least a part of the lower layer by laminating a Heusler alloy material layer made of a composition of cobalt, iron, and silicon and an iron-cobalt alloy layer in this order;
Forming a conductive layer on the iron-cobalt alloy layer as part of the spacer layer;
A step of laminating a raw material body made of any one of aluminum, silicon, chromium, titanium, and hafnium and a manganese layer on the conductive layer simultaneously or in advance,
Oxidizing at least a portion of the raw material body and at least a portion of the manganese layer;
Forming the upper layer on the raw material body and the manganese layer at least partially oxidized;
Having
Manufacturing method of magnetoresistive effect element. A lower layer, an upper layer, and a spacer layer sandwiched between the lower layer and the upper layer, and one of the lower layer and the upper layer has a magnetization direction fixed to an external magnetic field. The other of the lower layer and the upper layer changes its magnetization direction in response to the external magnetic field, and a sense current flows through each of the lower layer, the spacer layer, and the upper layer in a direction perpendicular to the film surface. A method of manufacturing a magnetoresistive element,
Forming the lower layer with an iron-cobalt alloy layer;
Forming a conductive layer on the iron-cobalt alloy layer as part of the spacer layer;
A step of laminating a raw material body made of any one of aluminum, silicon, chromium, titanium, and hafnium and a manganese layer on the conductive layer simultaneously or in advance,
Oxidizing at least a portion of the raw material body and at least a portion of the manganese layer;
Forming the upper layer on the raw material body and the manganese layer at least partially oxidized;
Having
Manufacturing method of magnetoresistive effect element.

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