JP3603062B2 - Magnetoresistive element, method of manufacturing the same, and magnetic device using the same - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a magnetoresistance effect element (hereinafter, referred to as “MR element”) and a method for manufacturing the same. The present invention further relates to a magnetic device using an MR element, for example, a magnetoresistive head (hereinafter, referred to as “MR head”), and a magnetic recording / reproducing device (for example, a hard disk device).
[0002]
[Prior art]
In order to cope with higher density of magnetic recording, a reproducing magnetic head using a GMR element has been developed. Further, in order to cope with further densification, a TMR (Tunnel Magnetoresence) element having a large resistance change and a large resistance itself has been actively studied. In a TMR element, an insulating layer is used as a nonmagnetic layer, and a tunnel current passing through the insulating layer is used. Normally, the GMR element is used by passing a current parallel to the film surface (CIP-GMR; Current in Plane-GMR), but like the TMR element, a device that allows a current to flow perpendicular to the film surface (CPP-GMR: Current) Perpendicular to the Plane-GMR) has also been proposed. The CPP-GMR element has an MR ratio about five times higher than that of the CIP-GMR element in Co / Cu, Co / Ag and the like.
[0003]
[Problems to be solved by the invention]
In the CPP-GMR element, a metal layer is used for the non-magnetic layer, and a current flows perpendicularly to the film surface. Therefore, the resistance is too low for use in a device. If the element is miniaturized, a certain degree of high resistance can be realized even in the CPP-GMR element. However, simply applying the lithography technique to reduce the size does not provide a CPP-GMR element having a sufficiently high resistance.
[0004]
As the density of magnetic recording increases, the track width of a recording medium decreases. For this reason, in the read magnetic head, it is necessary to reduce the width of a region (hereinafter, referred to as a “track corresponding width”) in which information is read by sensing magnetism from the medium. For example, in high-density magnetic recording of about 100 Gbit / in ² or more, a track width of 0.1 μm or less is required. However, as the track width becomes narrower, it is expected that the lithography technique alone will not be able to cope with it even if the technological progress is taken into account.
[0005]
An object of the present invention is to increase the electric resistance of a CPP-GMR element to a practical range. Another object of the present invention is to provide an MR element that can cope with a reduction in track width.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention includes a nonmagnetic layer, a first magnetic layer and a second magnetic layer sandwiching the nonmagnetic layer, wherein the magnetization direction of the first magnetic layer and the second magnetic layer An improvement has been made to the MR element in which a current for sensing a change in electric resistance based on a change in the angle relative to the magnetization direction flows perpendicularly to the film surface of each layer. The MR element of the present invention has an area of a nonmagnetic layer of 1 μm 2 or less, and has an oxide film, a nitride film or an oxynitride film of a constituent material of the magnetic layer on a side surface of the first or second magnetic layer. It is characterized by having.
[0007]
The method of manufacturing an MR element according to the present invention includes the steps of: forming a first magnetic layer, a nonmagnetic layer, and a second magnetic layer so that the area of the nonmagnetic layer is 1 μm ² or less when manufacturing the MR element; A step of oxidizing, nitriding, or oxynitriding a part of the at least one layer from the side surface of at least one layer selected from a first magnetic layer, a nonmagnetic layer, and a second magnetic layer.
[0008]
When the present invention is applied to a CPP-GMR element, an element having sufficiently high resistance can be obtained. Further, it is also possible to limit the track width of the magnetic head using this element. The present invention is also effective for reducing the track width of a magnetic head using a TMR element. The present invention further provides a magnetic head (MR head) using the above MR element and a magnetic recording / reproducing apparatus using the magnetic head.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of the present invention will be described.
According to the present invention, the second region made of the oxide film, the nitride film, or the oxynitride film increases the resistance value or narrows the track width. The area of the second region is preferably at least 10%, especially at least 40% of the area of the nonmagnetic layer. The second region is formed in at least one layer constituting an MR element whose non-magnetic layer has an area of 1 μm ² or less and is reduced in size to some extent. If the present invention is applied to an MR element which has a nonmagnetic layer having an area of 0.1 μm ² or less, particularly 0.01 μm ² or less, and is further miniaturized to some extent, better results can be obtained.
[0010]
When the present invention is applied to a CPP-GMR element, the first region and the second region may be formed at least in the nonmagnetic layer. In this case, the first region of the nonmagnetic layer is a metal film, preferably a film mainly containing at least one selected from Cu, Ag, Au, Ir, Ru, Rh and Cr. In the present specification, the main component refers to a component occupying 50% by weight or more.
[0011]
The second region is an oxide film, a nitride film or an oxynitride film of the metal constituting the first region. Since the conductive region (first region) of the nonmagnetic layer is limited by the second region, the resistance value of the element increases. There is a limit to the increase in the resistance value simply by finely processing the element. For example, in an element processed to 100 nm × 100 nm (element area of 0.01 μm ² ), the element resistance is about 1.5 Ω even if the element thickness is 50 nm and the specific resistance is 30 μΩcm. On the other hand, when the present invention is applied to a CPP-GMR element having the above element area, an element resistance of 3Ω or more can be obtained.
[0012]
The thickness of the nonmagnetic layer in the CPP-GMR element is preferably from 0.8 nm to 10 nm, particularly preferably from 1.8 nm to 5 nm. If the nonmagnetic layer is too thin, the interaction between the magnetic layers will be too strong. Conversely, if the nonmagnetic layer is too thick, a large MR ratio cannot be obtained.
[0013]
When the present invention is applied to a TMR element, the first region and the second region may be formed in at least one of the magnetic layers, that is, the first magnetic layer or the second magnetic layer. The nonmagnetic layer in this element is an insulating layer (tunnel insulating layer), preferably a layer mainly containing at least one selected from aluminum oxide, aluminum nitride, aluminum oxynitride, magnesium oxide and strontium titanate. Originally, it has a sufficiently high element resistance. However, also in this element, the restriction of the conductive region by the second region is effective for reducing the track width of the magnetic head using the second region. When the second region is formed by oxidizing at least one of the magnetic layers, a region for supplying a tunnel current to the insulating layer is limited. Therefore, a portion functioning as an element, that is, a region for sensing magnetism from a medium is substantially limited.
[0014]
The thickness of the nonmagnetic layer in the TMR element is preferably from 0.4 nm to 2 nm, particularly preferably from 0.4 nm to 1 nm in order to allow a tunnel current to flow.
[0015]
The MR element of the present invention may further include a magnetization rotation control layer magnetically coupled to at least one layer selected from the first magnetic layer and the second magnetic layer. The magnetization rotation control layer is not particularly limited as long as this layer facilitates or makes the magnetization rotation of the magnetic layer magnetically coupled, but an antiferromagnetic layer can be used, for example.
[0016]
By using a magnetization rotation control layer or the like, the element of the present invention may be a so-called spin valve type MR element. In this element, for example, while the magnetization rotation of one magnetic layer (fixed magnetic layer) is fixed by the exchange bias magnetic field with the antiferromagnetic layer, the magnetization of the other magnetic layer (free magnetic layer) is rotated by an external magnetic field. To detect the change in resistance.
[0017]
The second region can be formed, for example, by introducing oxygen and / or nitrogen to the side surface of the layer. This step may be performed by introducing a gas containing at least one selected from oxygen atoms and nitrogen atoms to the side surface of the layer while the layer is heated to 100 ° C. or higher. Further, at least one selected from oxygen ions and nitrogen ions may be implanted into the side surface of the layer. There is no limitation on the method of ion implantation itself, and it is sufficient to apply a known method.
[0018]
In a process such as oxidation, oxidation of an electrode, particularly an electrode formed before a nonmagnetic layer, may be a problem. In this case, the oxidation or the like may be performed after forming a protective film covering at least a part of the electrode formed beforehand, preferably so as not to cover the side surface to be oxidized or the like.
[0019]
The step of oxidation or the like is preferably performed on at least the side surface of the nonmagnetic layer in the case of the CPP-GMR element. On the other hand, in the case of the TMR element, the operation is performed on the first magnetic layer and / or the second magnetic layer. In any device, there is no limitation on the layer to be oxidized, nitrided or oxynitrided as long as the operation of the device is not hindered, and all of the first and second magnetic layers and the non-magnetic layer are oxidized or the like. No problem. Note that any of oxidation, nitridation, and oxynitridation may be applied; however, oxidation is preferable to obtain a high resistance value.
[0020]
Hereinafter, an example of an MR element to which the present invention is applied will be described with reference to the drawings. In the MR element 100 shown in FIG. 1, a lower electrode 2, an MR element part 10, and upper electrodes 3 and 4 are laminated on a substrate 1 in this order. An insulating film 5 is interposed between the two electrodes. The periphery of the MR element section 10 is oxidized to form an oxidized region (oxide film) 20. As illustrated, the oxidized region may extend to a part 2a, 3a of the electrodes 2, 3 as long as the function as an electrode is maintained.
[0021]
As shown in an enlarged view in FIG. 2, the MR element section 10 has a free magnetic layer 6, a nonmagnetic layer 7, a fixed magnetic layer 8, and an antiferromagnetic layer 9 laminated in this order from the substrate side. Since each of these layers is oxidized from the side surface, a current flowing perpendicularly to the film surface of each layer passes not through the oxidized region 20 but substantially through the central non-oxidized region 30. In the TMR element, the magnetic layer is originally an insulating layer, but since the magnetic layers 6 and 8 are oxidized, the tunnel current also passes through the non-oxidized region 30.
[0022]
This MR element can be formed by oxidizing the side surfaces of the multilayer film shown in FIG. The area of the portion to be operated by oxidation, as an element is lowered from the area S ₁ to the area S _2. Strictly speaking, the region that operates as an element is defined at the interface between the nonmagnetic layer and the magnetic layer. As described above, in a preferred embodiment of the present invention, by previously lithography limits the area S ₁ of the non-magnetic layer to 0.01 [mu] m ² or less, reducing the area until the S ₂ by further oxidation. The preferred ratio of the area _(S 1 -S ₂₎ to the area _{S 1 ((S 1 -S 2} ) / S 1) is 0.1 or more, particularly 0.4 or more.
[0023]
Hereinafter, the material of each layer is illustrated. Fe, Ni—Fe, Ni—Co—Fe, or a Co—Fe alloy is suitable for the free magnetic layer 6 in order to obtain good soft magnetic properties. The composition of Ni—Co—Fe (atomic composition ratio; the same applies hereinafter) is represented by Ni _x Co _y Fe _z , and 0.6 ≦ x ≦ 0.9, 0 ≦ y ≦ 0.4, 0 ≦ z ≦ A Ni-rich composition of 0.3 or a Co-rich composition of 0 ≦ x ≦ 0.4, 0.2 ≦ y ≦ 0.95, 0 ≦ z ≦ 0.5 is suitable. Films having these compositions have low magnetostriction characteristics (magnetostriction constant: 1 × 10 ⁻⁵ or less) required for magnetic sensors and MR heads. For the free magnetic layer, an amorphous film having a composition such as Co-Mn-B, Co-Fe-B, Co-Nb-Zr, or Co-Nb-B may be used.
[0024]
The thickness of the free magnetic layer 6 is preferably 1 nm to 10 nm. If the film thickness is too thick, the resistance not contributing to the MR increases and the MR ratio decreases, but if too thin, the soft magnetic characteristics deteriorate.
[0025]
For the non-magnetic layer 7 of the CPP-GMR element, a non-magnetic metal material is used. An insulating material is used for the non-magnetic layer 7 of the TMR element. Preferred materials and film thicknesses are as exemplified above.
[0026]
The material of the fixed magnetic layer 8, depending on the material of the free magnetic layer, Fe, Co, (displayed in particular by _{Co 1-x Fe x 0 <} x ≦ 0.5) Co-Fe alloy, Co- Ni-Fe alloys are suitable. This is for obtaining a large MR ratio. When Cr is used for the nonmagnetic layer, Fe is preferable. In this case, Fe may be used also for the free magnetic layer. When Cu is used in combination with the non-magnetic film, the Co _1-x Fe _x alloy has a large spin-dependent scattering and a large MR ratio.
[0027]
If the thickness of the fixed magnetic layer 8 is too small, the MR ratio decreases. If the thickness is too large, the exchange bias magnetic field decreases.
[0028]
Examples of the material of the antiferromagnetic layer 9 include Fe-Mn, Ni-Mn, Pd-Mn, Pt-Mn, Ir-Mn, Cr-Al, Cr-Mn-Pt, Fe-Mn-Rh, and Pd-Pt-. At least one selected from Mn, Ru-Rh-Mn, Mn-Ru and Cr-Al is preferred. From the viewpoint of corrosion resistance and thermal stability, a Mn-based antiferromagnetic material, specifically, Ni-Mn, Ir-Mn, Pt-Mn, particularly Pt-Mn is excellent. The composition of Pt _z Mn _1-z is preferably in the range of 0.45 ≦ z ≦ 0.55. The thickness of the antiferromagnetic layer is preferably 5 nm or more, particularly 10 nm or more in order to increase the bias effect.
[0029]
When Cu is used as the nonmagnetic layer, Co or a Co—Fe alloy is inserted as an interface magnetic layer at the interface between the ferromagnetic film (the free layer 6 and the fixed layer 8) and the nonmagnetic layer 7. Is preferred. This is because the MR ratio becomes larger. If the thickness of the interface magnetic layer is too large, the magnetic field sensitivity of the MR ratio is reduced. Therefore, the thickness is preferably 2 nm or less, particularly 1 nm or less. If the thickness is too small, the MR ratio does not improve.
[0030]
In order to increase the bias magnetic field applied to the pinned magnetic layer 8 (pinned layer), in other words, to stabilize the magnetization direction of the pinned layer, the pinned magnetic layer has three layers of a ferromagnetic layer / non-magnetic layer / ferromagnetic layer. May be used. In the indirect exchange coupling film, when an appropriate material and thickness are selected for the ferromagnetic layer and the nonmagnetic layer, a large antiferromagnetic coupling occurs between the ferromagnetic layers, and the magnetization of the fixed magnetic layer is further stabilized.
[0031]
Suitable materials for the ferromagnetic layer constituting the indirect exchange coupling film include Co, Co-Fe, Co-Fe-Ni alloy and the like, and Co and Co-Fe alloy are excellent. Suitable materials for the intermediate nonmagnetic layer include Ru, Ir, Rh and the like, and Ru is excellent. The thickness of the ferromagnetic layer is preferably 1 nm to 4 nm. The suitable thickness of the nonmagnetic layer is 0.3 nm to 1.2 nm, particularly 0.4 nm to 0.9 nm.
[0032]
As the lower electrode 2 and the upper electrodes 3 and 4, various non-magnetic metal materials such as Au, Ag, Cu, Pt, Ta, and Cr may be used.
[0033]
The configuration of the MR element unit 10 is not limited to the examples shown in FIGS. For example, the nonmagnetic layer and the magnetic layer may be further alternately stacked. In this case, at least one set of the magnetic layer / nonmagnetic layer / magnetic layer may have the configuration described above.
[0034]
Next, an example of a method for manufacturing an MR element of the present invention will be described with reference to the drawings.
First, as shown in FIG. 4, a lower electrode 2, an MR element portion 10, and an upper electrode 3 are sequentially stacked on a substrate 1. Next, as shown in FIG. 5, a photoresist 41 is applied and exposed, and ion milling is performed to form the lower electrode 2 into a predetermined shape. Further, as shown in FIG. 6, a photoresist 42 is applied again, exposed, ion-milled, and shaped so that the area of the non-magnetic layer in the MR element section 10 becomes 1 μm ² or less. This ion milling is preferably performed until part of the lower electrode 2 is milled.
[0035]
Subsequently, as shown in FIG. 7, after forming an insulating film 45 as a protective film by vapor deposition or the like, oxygen ions 43 are implanted. Oxygen ions are preferably applied obliquely to the film surface so that the side surfaces of the element 10 are oxidized. If necessary, oxygen gas may be introduced into the side surface of the element while heating in vacuum. Since the side surface of the element is made amorphous by ion implantation, when oxygen is introduced into this side surface, the oxide film 20 is easily formed.
[0036]
The method of forming the oxide film 20 is not limited to ion implantation, and may be performed by introducing oxygen gas to the side surface of the element heated to 100 ° C. or higher. Further, as long as the object of the present invention is achieved, a plasma oxidation method or a natural oxidation method may be used. A nitride film or an oxynitride film may be formed instead of the oxide film.
[0037]
After the oxidation, as shown in FIG. 8, an insulating film 5 is further formed by vapor deposition or the like. As illustrated, the protective insulating film 45 formed earlier may be a part of the insulating film 5. As shown in FIG. 9, after the excess insulating film 5 is lifted off, an additional upper electrode 4 is formed by vapor deposition or the like. Thus, the MR element 100 is completed. The layers may be formed by a conventionally used method. For example, the layers of the MR element unit 10 may be formed by various sputtering methods, vapor deposition methods, or the like.
[0038]
FIG. 10 shows an example of an MR head using the MR element 100. As shown in FIG. 12, in the MR head 220 using the CIP-GMR element, a current flows between the electrodes 19a and 19b in a direction parallel to the film surface of the MR element 120, but in the MR head 200 in FIG. A current flows in the direction perpendicular to the film surface of the MR element 100. As shown in FIG. 11, the MR head 210 itself to flow current perpendicular to the film surface of the element, has been known conventionally, the MR head of FIG. 10, the track corresponding width W ₁ of the head is conventional track corresponding It is narrowed than the width W _2. Track corresponding width _{W 1} is, 0.1 [mu] m or less, particularly 0.01~0.1μm is preferred.
[0039]
The MR head 220 shown in FIG. 12 requires an insulating region 17 (usually an insulating film is used) for securing insulation between the magnetic shields 13 and 16. On the other hand, in the magnetic head of FIG. 10, if the upper magnetic shield 13 and the lower magnetic shield 16 are used as electrodes, the electrodes 2 and 3 can be omitted. As described above, if a magnetic shield that suppresses the flow of an extra magnetic field other than the signal magnetic field into the MR element is used as an electrode, it is easy to cope with a narrow gap accompanying high-density recording.
[0040]
In these magnetic heads, a recording head that shares one of the magnetic shields with the reproducing head is arranged in contact with the reproducing head. The recording head includes a recording magnetic pole (upper shield) 12, a common shield 13, an insulating film 14 interposed between the shields, and a winding 11.
[0041]
For the upper, common, and lower magnetic shields 12, 13, and 16, a soft magnetic film such as a Ni-Fe, Fe-Al-Si, or Co-Nb-Zr alloy may be used. Al ₂ O ₃ , AlN, SiO ₂ or the like is suitable for the insulating films 14 and 15.
[0042]
Note that a ferromagnetic bias layer (not shown) made of Co-Pt or the like may be provided on both sides of the magnetoresistive effect element 10 in order to suppress the occurrence of Barkhausen noise.
[0043]
FIGS. 13 and 14 are a plan view and a side view of a hard disk drive 300 using the MR head 200, respectively. The hard disk drive 300 has a slider 120 having an MR head (not shown), a head support mechanism 130 supporting the slider, an actuator 114 tracking the MR head via the head support mechanism 130, and recording information by the head. And a disk drive motor 112 for rotating a magnetic disk 116 for reproduction / reproduction. The head support mechanism 130 includes an arm 122 and a suspension 124.
[0044]
The disk drive motor 112 rotates the disk 116 at a predetermined speed. The actuator 114 moves a slider 120 holding the MR head in a radial direction of the disk 116 so that the MR head can access a predetermined data track of the disk. The actuator 114 is, for example, a linear or rotary voice coil motor. The slider 120 is, for example, an air bearing slider. In this case, the slider 120 comes into contact with the surface of the disk 116 when the hard disk device 300 starts / stops. On the other hand, during the information recording / reproducing operation, the slider 120 floats above the surface of the disk by the air bearing formed between the rotating disk 116 and the slider 120. In this state, information is recorded and / or reproduced on the magnetic disk 116 by the MR head 200.
[0045]
【Example】
(Example 1)
An MR element was formed using a multi-source sputtering apparatus. The MR element portion has a so-called dual spin valve structure in which fixed layers are arranged on both sides of a free layer via a nonmagnetic layer. The laminated structure of this element is shown below together with the substrate and the electrodes.
[0046]
Substrate / Au (500) / Pt _0.5 Mn _0.5 (30) / CoFe (3) / Ru (0.7) / CoFe (3) / Cu (3) / CoFe (2) / NiFe (5) _{/CoFe(2)/Cu(3)/CoFe(3)/Ru(0.7)/CoFe(3)/Pt 0.5 Mn 0.5 (30) /} Au (500)
However, the numerical value in parentheses is the film thickness (unit: nm; the same applies hereinafter).
[0047]
Cu is a nonmagnetic layer, PtMn is an antiferromagnetic layer, and Au is an electrode. Note that Si whose surface was thermally oxidized was used as the substrate.
[0048]
The CPP-GMR element portion thus obtained was processed into an MR element by the method described above with reference to FIGS. The size of the patterning using the photoresist was 100 nm × 100 nm. Note that an SiO ₂ film was used for the insulating film (reference numerals 5 and 45 in FIGS. 7 and 8). The oxide film 20 was formed by implanting 30 keV oxygen ions from a direction inclined at about 45 degrees with respect to the film surface. The implantation amount of oxygen ions was 1 × 10 ¹⁵ ions / cm ² . When oxidation cannot be sufficiently performed by ion implantation, oxygen gas may be further introduced while being heated to 200 to 300 ° C. in vacuum. Thus, when oxidation was performed from one side surface of the element, a Cu oxide film was formed on the nonmagnetic layer to a depth of 45 nm from the side surface. As shown, the oxidation may be performed from both sides.
[0049]
Along with the thus obtained MR element (element A), an MR element (element B) was produced in the same manner as above except that the side surface oxidation step was omitted. The magnetoresistance characteristics of both devices were evaluated by applying a magnetic field of 500 Oe (about 39.8 kA / m) at room temperature and using a four-terminal method. The element A having the oxidized side surface had a resistance of 3Ω, a resistance change of 0.9Ω, and an MR ratio of 30%, whereas the conventional element B had a resistance of 1.5Ω and a resistance change of 0.45Ω. , MR ratio was 30%. It was confirmed that the resistance change amount was doubled by oxidizing the side surface.
[0050]
Further, MR heads 200 and 210 as shown in FIGS. 10 and 11 were manufactured in the same manner as above. Ni _0.8 Fe _0.2 alloy was used for the magnetic shield, and Al ₂ O ₃ was used for the insulating film. The electrodes were replaced by magnetic shields. An Al ₂ O ₃ —TiC substrate was used as a substrate for forming each layer. A DC current was passed as a sense current to both heads thus obtained, and an AC signal magnetic field of about 4 kA / m was applied to evaluate the output of both heads. The output of the MR head corresponding to FIG. 10 was about twice the output of the MR head corresponding to FIG.
[0051]
(Example 2)
An MR element was formed using a multi-source sputtering apparatus. The laminated structure of this element is shown below together with the substrate and the electrodes.
[0052]
Substrate / Au (500) / Pt _0.5 Mn _0.5 (30) / CoFe (3) / Ru (0.7) / CoFe (3) / Al ₂ O ₃ (0.8) / CoFe (2) / NiFe (5) / Au (500)
[0053]
Note that the nonmagnetic layer Al ₂ O ₃ film was formed by oxidizing the formed Al by a natural oxidation method. The TMR element portion thus obtained was processed into an MR element in the same manner as in Example 1 to obtain an MR element (element C) whose side surface was oxidized and an MR element (element D) manufactured without the side surface oxidation step. Was.
[0054]
When both elements were observed using a transmission electron microscope, in the element C, both magnetic layers sandwiching the nonmagnetic layer were oxidized from the side. The width of the non-oxidized region was about 50 nm. On the other hand, in the device D, no oxidized region was observed, and the width of the region functioning as the device remained at about 100 nm.
[0055]
【The invention's effect】
As described above, according to the present invention, in the MR element in which a current flows perpendicularly to the film surface, the electric resistance is increased to a practical range, or the track width is increased to a level that is difficult with a lithographic technique. Can be reduced.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an example of an MR element of the present invention.
FIG. 2 is an enlarged view of an MR element part of the element of FIG.
FIG. 3 is a cross-sectional view showing an example of a multilayer film for forming the element section of FIG.
FIG. 4 is a cross-sectional view for explaining one step (lamination step of each layer) in an example of the manufacturing method of the present invention.
FIG. 5 is a cross-sectional view for explaining a step of processing the laminate of FIG.
FIG. 6 is a cross-sectional view for explaining a step of further processing the laminate of FIG. 5;
FIG. 7 is a cross-sectional view illustrating a step of partially oxidizing the laminate of FIG. 6;
FIG. 8 is a cross-sectional view for explaining a step of further forming an insulating film on the laminate of FIG.
FIG. 9 is a cross-sectional view illustrating a step of forming an additional upper electrode on the laminate of FIG. 8;
FIG. 10 is a partial perspective view showing an example of the MR head of the present invention.
FIG. 11 is a partial perspective view of a conventional MR head.
FIG. 12 is a partial perspective view of a conventional MR head using a CIP-GMR element.
FIG. 13 is a plan view showing an example of the magnetic recording / reproducing apparatus of the present invention.
14 is a sectional view of the magnetic recording / reproducing apparatus of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Substrate 2 Lower electrode 3, 4 Upper electrode 5 Insulating film 6 Free magnetic layer 7 Nonmagnetic layer 8 Fixed magnetic layer 9 Antiferromagnetic layer 10 MR element part 20 Oxidized area 30 Non-oxidized area

Claims (19)

A non-magnetic layer, and a first magnetic layer and a second magnetic layer sandwiching the non-magnetic layer, based on a change in a relative angle between a magnetization direction of the first magnetic layer and a magnetization direction of the second magnetic layer. A magnetoresistive element that allows a current for sensing a change in electrical resistance to flow in a direction perpendicular to the film surface of each of the layers,
The area of the nonmagnetic layer is 1 μm ² or less,
A magnetoresistive element having an oxide film, a nitride film, or an oxynitride film of a constituent material of the magnetic layer on a side surface of the first or second magnetic layer. 2. The magnetoresistive device according to claim 1, wherein the area of the oxide film, the nitride film, or the oxynitride film occupies at least 10% of the total area of the magnetic layer, the oxide film, the nitride film or the oxynitride film, and the magnetic layer. Effect element. 3. The magnetoresistive element according to claim 1, wherein the area of the nonmagnetic layer is 0.1 μm ² or less. The magnetoresistance effect element according to claim 1, wherein the nonmagnetic layer is an insulating layer. 5. The magnetoresistance effect element according to claim 1, wherein the nonmagnetic layer contains at least one selected from aluminum oxide, aluminum nitride, aluminum oxynitride, magnesium oxide and strontium titanate as a main component. 6. The magnetoresistive element according to claim 1 , wherein the thickness of the nonmagnetic layer is 0.4 nm or more and 2 nm or less. 7. The magnetoresistive element according to claim 1, further comprising a magnetization rotation control layer magnetically coupled to at least one layer selected from a first magnetic layer and a second magnetic layer. The magnetoresistance effect element according to claim 7, wherein the magnetization rotation control layer is an antiferromagnetic layer. A non-magnetic layer, and a first magnetic layer and a second magnetic layer sandwiching the non-magnetic layer, based on a change in a relative angle between a magnetization direction of the first magnetic layer and a magnetization direction of the second magnetic layer. A method for manufacturing a magnetoresistive element, in which a current for sensing a change in electric resistance is caused to flow perpendicular to a film surface of each of the layers,
Forming the first magnetic layer, the nonmagnetic layer, and the second magnetic layer such that the area of the nonmagnetic layer is 1 μm ² or less;
Oxidizing, nitriding, or oxynitriding a part of the at least one layer from a side surface of at least one layer selected from the first magnetic layer, the nonmagnetic layer, and the second magnetic layer. A method for manufacturing a magnetoresistive element. 10. The magnet according to claim 9, wherein the layer is oxidized, nitrided or oxynitrided by introducing a gas containing at least one selected from oxygen atoms and nitrogen atoms to a side surface of the layer while the layer is heated to 100 ° C or higher. A method for manufacturing a resistance effect element. The method for manufacturing a magnetoresistive element according to claim 9, wherein oxidation, nitridation, or oxynitridation is performed by injecting at least one selected from oxygen ions and nitrogen ions into the side surfaces of the layer. Forming an electrode for passing an electric current, and forming a protective film covering at least a part of the electrode, and after forming the protective film, oxidizing, nitriding or oxynitriding a part of the layer; A method for manufacturing a magnetoresistive element according to any one of claims 9 to 11 . The manufacturing of the magnetoresistive element according to any one of claims 9 to 12, wherein a layer mainly composed of at least one selected from Cu, Ag, Au, Ir, Ru, Rh and Cr is formed as the nonmagnetic layer. Method. 14. The method for manufacturing a magnetoresistive element according to claim 13, wherein at least a side surface of the nonmagnetic layer is oxidized, nitrided, or oxynitrided. The method according to claim 9, wherein an insulating layer is formed as the nonmagnetic layer. The method according to claim 15, wherein at least a side surface of the first magnetic layer or the second magnetic layer is oxidized, nitrided, or oxynitrided. A magnetoresistive head comprising: the magnetoresistive element according to claim 1; and a pair of magnetic shields arranged so as to sandwich the magnetoresistive element. The magnetoresistive head according to claim 17, wherein a track corresponding width is 0.1 μm or less. 19. A magnetic recording / reproducing apparatus comprising: the magnetoresistive head according to claim 17; and a magnetic recording medium for recording / reproducing information with the head.

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