JP2004006494A - Giant magnetoresistive effect element and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a giant magnetoresistive effect element that can reduce the disturbance of magnetization in the edge area of a synthetic free ferrimagnetic layer, and to obtain a method of manufacturing the element. <P>SOLUTION: In a GMR element 1 having a synthetic free ferrimagnetic layer 10 constituted by laminating a first magnetic layer 11, a nonmagnetic layer 13, and a second magnetic layer 12 upon another and a hard bias layer 8, the first magnetic layer 11 has a main magnetic layer 11 which is formed correspondingly to a track-width area and is in contact with the hard bias layer 8 at both side end sections in the track width direction and an auxiliary magnetic layer 11b laminated upon the main magnetic layer 11a and hard bias layer 8 astride the layers 11a and 8. The total film thickness D1 of the main and auxiliary magnetic layers 11a and 11b is made larger than the film thickness D2 of the second magnetic layer 12 so that a RKKY-like anti-parallel coupling may be generated between the auxiliary and second magnetic layers 11b and 12. In addition, the dimensions T2 of the auxiliary magnetic layer 11b, nonmagnetic layer 13, and second magnetic layer 12 in the track width direction are made larger than that T1 of the main magnetic layer 11a in the same direction. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a giant magnetoresistance effect element used for a hard disk drive, a magnetic sensor, and the like, and a method for manufacturing the same.
[0002]
[Prior art and its problems]
In a giant magnetoresistive (GMR) element used for a hard disk device, a magnetic sensor, and the like, a high output sensitivity has been promoted with a recent increase in recording density. Conventionally, by reducing the thickness of the free magnetic layer, the magnetic moment per unit area of the free magnetic layer (Areal moment) is reduced, thereby facilitating magnetization rotation of the magnetic moment per unit area and improving output sensitivity. Let me. However, when the thickness of the free magnetic layer is reduced, Barkhausen noise, thermal fluctuation noise, and the like increase. As a result, there is a disadvantage that the SN ratio does not increase even if the output sensitivity increases.
[0003]
Therefore, recently, it has been proposed that the free magnetic layer has a laminated ferrimagnetic (artificial ferrimagnetic) structure. In the laminated ferrimagnetic free magnetic layer 100 shown in FIG. 11, a nonmagnetic layer 130 is interposed between a first magnetic layer 110 and a second magnetic layer 120, and the first magnetic layer 110 is interposed via the nonmagnetic layer 130. And the second magnetic layer 120 are firmly antiparallel-coupled. The vector sum of the magnetic moment m1 per unit area of the first magnetic layer 110 and the magnetic moment m2 per unit area of the second magnetic layer 120 is the magnetic moment M per unit area of the free magnetic layer 100. . This makes it possible to reduce the effective magnetic moment per unit area of the free magnetic layer without reducing the thickness of the free magnetic layer, thereby suppressing noise and improving output sensitivity and SN ratio. In FIG. 11, the thickness of the first magnetic layer 110 is set to be larger than the thickness of the second magnetic layer 120.
[0004]
However, when the free magnetic layer has a laminated ferrimagnetic structure, the following problem occurs due to the hard bias layer (permanent magnet film) 80 provided for making the free magnetic layer a single magnetic domain. That is, in the edge region α of the free magnetic layer 100 adjacent to the hard bias layer 80, the magnetic field received from the hard bias layer 80 is stronger than the spin-flop magnetic field, and the magnetic field between the first magnetic layer 110 and the second magnetic layer 120 is smaller. The parallel coupling state is broken. Then, the magnetic field received from the hard bias layer 80 causes magnetic interference in the edge region α of the second magnetic layer 120 having the magnetization direction opposite to the magnetization direction of the hard bias layer 80, and this second magnetic layer 120 On the other hand, the magnetization of the first magnetic layer 110 that attempts to maintain the antiparallel state is also disturbed (see FIG. 12). Such disturbance of the magnetization in the edge region α of the free magnetic layer 100 has caused Barkhausen noise, servo error, and the like.
[0005]
On the other hand, it is considered that when the free magnetic layer is biased by the exchange bias method, it is possible to eliminate the disturbance of the magnetization in the edge region. However, the exchange bias method has a problem that the manufacturing process is complicated. There is a risk of side reading. For this reason, it is desirable that the above problem can be solved while using the conventional hard bias system.
[0006]
[Object of the invention]
The present invention provides a giant magnetoresistive element capable of reducing disturbance of magnetization in an edge region of a laminated ferrimagnetic free magnetic layer and preventing side reading, based on a problem awareness when a conventional free magnetic layer has a laminated ferrimagnetic structure. And a method for producing the same.
[0007]
Summary of the Invention
The present invention is intended to reduce the disturbance of the magnetization in the edge region by not directly opposing the second magnetic layer having the magnetization direction opposite to that of the hard bias layer to the hard bias layer. Further, by stabilizing the magnetization at both ends in the track width direction of the first magnetic layer and the second magnetic layer, side reading is prevented.
[0008]
That is, the present invention provides a laminated ferrimagnetic free magnetic layer comprising: a first magnetic layer; a nonmagnetic layer formed on the first magnetic layer; and a second magnetic layer formed on the nonmagnetic layer. A giant magnetoresistive element including a hard bias layer for aligning the magnetization direction of the first magnetic layer, wherein the first magnetic layer is formed corresponding to a track width region, and the hard bias is formed at both end portions in the track width direction. A main magnetic layer in contact with the layer, and an auxiliary magnetic layer laminated over the main magnetic layer and the hard bias layer. The total thickness of the main magnetic layer and the auxiliary magnetic layer The thickness of the auxiliary magnetic layer, the non-magnetic layer, and the second magnetic layer in the track width direction is longer than the main magnetic layer in the same direction. Wherein the non-magnetic layer is It is characterized in that it is formed in a thickness to cause the RKKY antiparallel coupling between the second magnetic layer.
[0009]
The auxiliary magnetic layer is preferably formed with a smaller thickness than the main magnetic layer. Specifically, for example, it is preferable that the main magnetic layer is formed to have a thickness of 15 ° to 50 ° and the auxiliary magnetic layer is formed to be 10 ° to 30 °.
[0010]
A nonmagnetic protective layer formed of a conductive nonmagnetic material may be interposed between the main magnetic layer and the auxiliary magnetic layer. This non-magnetic protective layer functions as a protective layer for preventing oxidation of the main magnetic layer surface during the manufacturing process. The thickness of the non-magnetic protective layer is set to a thickness that causes an RKKY-like parallel coupling between the main magnetic layer and the auxiliary magnetic layer or a direct exchange coupling effect via a pinhole of the non-magnetic protective layer. Specifically, if the nonmagnetic protective layer has a thickness of 6 mm or less, strong parallel coupling can be generated between the main magnetic layer and the auxiliary magnetic layer. This nonmagnetic protective layer is preferably formed of one or more of Ru, Rh, Pd, Ir, Os, Re, Cr, Cu, Pt, and Au. In particular, it is preferably formed of Cu.
[0011]
The first magnetic layer and the second magnetic layer are preferably formed of the same magnetic material, and can be formed of, for example, any of CoFe, NiFe, and CoFeNi. The hard bias layer is preferably formed of CoPt or CoCrPt.
[0012]
The nonmagnetic layer interposed between the first magnetic layer and the second magnetic layer may be any one or more of Ru, Rh, Pd, Ir, Os, Re, Cr, Cu, Pt, and Au. It is preferably formed. For example, when the non-magnetic layer is formed of Ru, its thickness is adjusted to 6 ° or more and 15 ° or less. When the nonmagnetic layer is formed of Cu, its thickness is adjusted to 7 ° or more and 12 ° or less.
[0013]
In the method for manufacturing a giant magnetoresistive element according to the present invention, (a) a laminate having an antiferromagnetic layer, a fixed magnetic layer, a nonmagnetic intermediate layer, a main magnetic layer of a first magnetic layer, and a nonmagnetic protective layer on a substrate Forming a body, (b) forming a resist layer on a track width region of the laminate, and (c) at least the non-magnetic layer of the laminate exposed from both sides of the resist layer in the track width direction. Removing the protective layer, the main magnetic layer and the non-magnetic intermediate layer, forming a hard bias layer on the removed portion, and removing the resist layer; and (d) removing the non-magnetic layer on the main magnetic layer. And (e) laminating an auxiliary magnetic layer, a non-magnetic layer, and a second magnetic layer of the first magnetic layer on the main magnetic layer and the hard bias layer. In the step (e), the non-magnetic layer is replaced with the complementary layer. The magnetic layer and the second magnetic layer are formed so as to have an RKKY-like antiparallel coupling between the magnetic layer and the second magnetic layer. The second magnetic layer has a thickness larger than the total thickness of the main magnetic layer and the auxiliary magnetic layer. The auxiliary magnetic layer, the non-magnetic layer, and the second magnetic layer are formed so as to have a smaller thickness in a track width direction than the main magnetic layer in the same direction. .
[0014]
In the present manufacturing method, instead of the above step (d), (f) a step of cutting the nonmagnetic protective layer on the main magnetic layer to a thickness that causes parallel coupling between the main magnetic layer and the auxiliary magnetic layer. Can be provided. Specifically, the thickness of the nonmagnetic protective layer is preferably set to 6 ° or less. If the nonmagnetic protective layer is left on the main magnetic layer at this thickness, the surface of the main magnetic layer is not damaged when the nonmagnetic protective layer is shaved, and the main magnetic layer and the auxiliary magnetic layer are firmly connected. Can be combined. In the step (d) or the step (f), it is preferable to use low-energy ion milling so that the thickness of the nonmagnetic protective layer can be adjusted accurately and easily.
[0015]
After the step (e), it is preferable to include a step (g) of performing annealing in a magnetic field to generate an exchange coupling magnetic field between the antiferromagnetic layer and the fixed magnetic layer. According to the annealing in the magnetic field, not only the magnetization direction of the fixed magnetic layer is fixed, but also the parallel coupling between the main magnetic layer and the auxiliary magnetic layer and the parallel coupling between the auxiliary magnetic layer and the hard bias layer can be stabilized.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with reference to the drawings. In each figure, the X direction is the track width direction, the Y direction is the direction of the leakage magnetic field from the recording medium, and the Z direction is the moving direction of the recording medium and the laminating direction of each layer constituting the giant magnetoresistance effect element.
[0017]
FIG. 1 is a schematic sectional view showing the structure of a giant magnetoresistive (GMR) element 1 according to a first embodiment of the present invention, as viewed from a surface facing a recording medium. The GMR element 1 is used, for example, in a thin-film magnetic head of a hard disk device, and detects a leakage magnetic field from a recording medium using the GMR effect.
[0018]
The GMR element 1 is made of alumina (Al ₂ O ₃ ) Is formed on the lower gap layer 2 made of an insulating material such as a seed layer 3, an antiferromagnetic layer 4, a fixed magnetic layer 5, a nonmagnetic intermediate layer 6, and a free magnetic layer in order from the lower gap layer 2 side. It has ten. Although not shown, an insulating layer such as alumina, an underlayer made of Ta or Ti, a seed layer made of NiFe alloy or the like, a NiFe-based alloy or the like are provided under the lower gap layer 2 in this order from the Altic substrate side. A lower shield layer made of a magnetic material is formed.
[0019]
The seed layer 3 is an underlayer for adjusting the crystal growth of the antiferromagnetic layer 4 and each layer on the antiferromagnetic layer 4, and is formed of a NiFe alloy, a NiCr alloy, a NiFeCr alloy, Cr, or the like. An underlayer made of Ta or the like may be formed between the seed layer 3 and the lower gap layer 2, or the underlayer may be formed instead of the seed layer 3.
[0020]
The antiferromagnetic layer 4 generates a large exchange coupling magnetic field with the fixed magnetic layer 5 by heat treatment, and fixes the magnetization direction of the fixed magnetic layer 5 in the Y direction in the figure. The antiferromagnetic layer 4 is formed of a PtMn alloy or an X-Mn alloy (where X is at least one element of Pd, Ir, Rh, Ru, Os, Ni, and Fe). You. Alternatively, Pt—Mn—X ′ (where X ′ is any one or more of Pd, Ir, Rh, Ru, Au, Ag, Os, Cr, Ni, Ar, Ne, Xe, and Kr) A) alloy. These alloys have an irregular face-centered cubic structure (fcc) immediately after film formation, but have a CuAuI (CuAu1) type regular face-centered square structure (fct) when subjected to heat treatment. Pervert.
[0021]
The fixed magnetic layer 5 is formed of a magnetic material such as a NiFe alloy, Co, a CoNiFe alloy, a CoFe alloy, or a CoNi alloy. The fixed magnetic layer 5 may have a laminated ferrimagnetic structure having a three-layer structure of a magnetic layer / non-magnetic layer / magnetic layer. If the pinned magnetic layer 5 has this laminated ferrimagnetic structure, the magnetization is enhanced by the synergistic effect of the antiparallel coupling between the magnetic layers via the nonmagnetic layer and the exchange coupling between the magnetic layer and the antiferromagnetic layer 4. The direction is fixed more stably.
[0022]
The nonmagnetic intermediate layer 6 is a layer that prevents magnetic coupling between the fixed magnetic layer 5 and the free magnetic layer 10, and is a layer through which a sense current mainly flows. The non-magnetic intermediate layer 6 is formed of a conductive non-magnetic material such as Cu, Cr, Au or Ag. In particular, it is preferably formed of Cu.
[0023]
The free magnetic layer 10 has a laminated ferrimagnetic structure. That is, the free magnetic layer 10 is composed of three layers, a first magnetic layer 11, a second magnetic layer 12, and a nonmagnetic layer 13 interposed therebetween. The two magnetic layers 12 are anti-parallel coupled RKKY.
[0024]
The first magnetic layer 11 has a T-shaped cross section including a main magnetic layer 11a corresponding to the track width region and an auxiliary magnetic layer 11b extending in the track width direction from the main magnetic layer 11a. The main magnetic layer 11a and the auxiliary magnetic layer 11b are ferromagnetically coupled (parallel coupled). The auxiliary magnetic layer 11b is laminated on the main magnetic layer 11a and the hard bias layers 8 located at both ends in the track width direction of the main magnetic layer 11a. And the nonmagnetic layer 13. The auxiliary magnetic layer 11b is formed with a thickness d1 'smaller than the thickness d1 of the main magnetic layer 11a. On the other hand, the second magnetic layer 12 is formed with a film thickness D2 smaller than the film thickness D1 of the first magnetic layer 11, and has a central portion 12a corresponding to the track width region and a track width direction from both sides of the central portion 12a. And an extended portion 12b. Here, the thickness D1 of the first magnetic layer 11 is the total thickness of the thickness d1 of the main magnetic layer 11a and the thickness d1 'of the auxiliary magnetic layer 11b. The second magnetic layer 12, the nonmagnetic layer 13, and the auxiliary magnetic layer 11b are formed in the track width direction with a dimension T2 longer than the dimension T1 of the main magnetic layer 11a. In the present embodiment, the dimension T1 of the main magnetic layer 11a in the track width direction regulates the track width Tw.
[0025]
The magnetic field (spin-flop magnetic field) when the antiparallel state between the first magnetic layer 11 and the second magnetic layer 12 breaks is set to be sufficiently large with respect to the leakage magnetic field from the recording medium. In other words, the magnetizations in the track width regions of the first magnetic layer 11 and the second magnetic layer 12 change together with the leakage magnetic field from the recording medium while maintaining the antiparallel state. That is, the magnetic moment M per unit area of the free magnetic layer 10 is the vector sum of the magnetic moment m1 per unit area of the first magnetic layer 11 and the magnetic moment m2 per unit area of the second magnetic layer 12. Therefore, the effective magnetic moment M per unit area of the free magnetic layer 10 can be reduced without reducing the thickness of the free magnetic layer 10. As a result, both the output sensitivity and the SN ratio can be increased without increasing Barkhausen noise and thermal fluctuation noise.
[0026]
The first magnetic layer 11 and the second magnetic layer 12 are preferably formed of the same magnetic material, for example, a CoFe alloy, a NiFe alloy, a CoFeNi alloy, or the like. On the other hand, the nonmagnetic layer 13 can be formed of one or more of Ru, Rh, Pd, Ir, Os, Re, Cr, Cu, Pt, and Au. Particularly, it is preferable to be formed of Ru or Cu. The nonmagnetic layer 13 is preferably formed to have a film thickness in which the RKKY-like binding energy generated between the auxiliary magnetic layer 11b and the second magnetic layer 12 has a first antiparallel peak value. For example, when the nonmagnetic layer 13 is formed of Ru, the film thickness is in the range of 6 ° to 15 °, and when formed of Cu, the film thickness is in the range of 7 ° to 12 °.
[0027]
A non-magnetic underlayer 7 and a hard bias layer 8 are sequentially stacked on both end portions in the track width direction of the seed layer 3, the antiferromagnetic layer 4, the fixed magnetic layer 5, the non-magnetic intermediate layer 6, and the main magnetic layer 11a. Is formed. The nonmagnetic underlayer 7 is provided to increase the coercive force of the hard bias layer 8, and is formed of a nonmagnetic material such as Cr, W, or Ti. The hard bias layer (permanent magnet film) 8 is made of, for example, CoPt or CoCrPt, and stabilizes the magnetization direction of the main magnetic layer 11a in the track width direction (to the right in FIG. 1).
[0028]
A protective layer 14 is formed on the extension 12b of the second magnetic layer 12, and an electrode lead layer E and a metal mask layer 15 are formed on the protective layer 14 in a laminated manner. The electrode lead layer E is formed of a conductive material such as Au or α-Ta by sputtering or the like, and is formed with holes in a range corresponding to a track width region by RIE (Reactive Ion Etching). The protective layer 14 is a layer that functions as a stopper during the RIE process, and is made of a non-magnetic metal material such as Ta or Cr having a low etching rate. The metal mask layer 15 is a layer that functions as a mask during the RIE process. This metal mask layer 15 preferably functions as a stopper for RIE, such as Ta or Cr, and is preferably formed of a non-magnetic metal material having a low etching rate. Note that an insulating mask layer made of an insulating material may be provided on the electrode lead layer E instead of the metal mask layer 15.
[0029]
Although not shown, an upper shield layer is formed on the metal mask layer 15 and the central portion 12a of the second magnetic layer 12 via an upper gap layer made of, for example, alumina.
[0030]
In the present GMR element 1, the first magnetic layer 11 is composed of the main magnetic layer 11a and the auxiliary magnetic layer 11b, and the auxiliary magnetic layer 11b, the nonmagnetic layer 13, and the second magnetic layer 12 have a dimension T2 in the track width direction. Is longer than the dimension T1 of the main magnetic layer 11a in the same direction. By making the auxiliary magnetic layer 11b, the nonmagnetic layer 13, and the second magnetic layer 12 longer than the main magnetic layer 11a in the track width direction, the auxiliary magnetic layer 11b and the hard bias layer 8 are ferromagnetically parallel. The magnetization direction of the extension 12b of the second magnetic layer 12 can be fixed to the direction opposite to the magnetization direction of the hard bias layer 8 via the auxiliary magnetic layer 11b and the nonmagnetic layer 13. Thereby, the magnetization of the free magnetic layer 10 does not change with respect to the leakage magnetic field of the recording medium outside the track width region, and side reading can be prevented.
[0031]
Further, by making the dimension T2 of the auxiliary magnetic layer 11b and the second magnetic layer 12 in the track width direction longer than the dimension T1 of the main magnetic layer 11a in the same direction, the second magnetic layer 12 and the hard bias layer 8 are directly connected. Without opposing, it is possible to reduce the disturbance of the magnetization of the second magnetic layer 12 due to the bias magnetic field. Further, even if the magnetization is disturbed in the extending portion 12b of the second magnetic layer 12, the influence on the central portion 12a of the second magnetic layer 12 can be reduced, and the magnetization in the track width region of the free magnetic layer 10 can be reduced. Disturbance can be suppressed. This eliminates the risk of causing Barkhausen noise, servo error, and the like as in the related art.
[0032]
Hereinafter, a method for manufacturing the GMR element 1 shown in FIG. 1 will be described with reference to FIGS. First, as shown in FIG. 2, a seed layer 3, an antiferromagnetic layer 4, a fixed magnetic layer 5, a nonmagnetic intermediate layer 6, a main magnetic layer 11a of a first magnetic layer 11, The non-magnetic protective layer 16 is continuously formed. Sputtering or vapor deposition is used for film formation.
[0033]
The seed layer 3 is formed of a NiFe alloy, a NiCr alloy, a NiFeCr alloy, Cr, or the like. The antiferromagnetic layer 4 is formed of a PtMn alloy or an X-Mn alloy (where X is one or more elements of Pd, Ir, Rh, Ru, Os, Ni, and Fe). Alternatively, Pt—Mn—X ′ (where X ′ is any one or more of Pd, Ir, Rh, Ru, Au, Ag, Os, Cr, Ni, Ar, Ne, Xe, and Kr) A) alloy. If the antiferromagnetic layer 4 is formed from such an alloy material, a large exchange coupling magnetic field can be generated in a subsequent magnetic field annealing process.
[0034]
The fixed magnetic layer 5 is formed of a magnetic material such as a NiFe alloy, Co, a CoNiFe alloy, a CoFe alloy, or a CoNi alloy. This fixed magnetic layer 5 may be formed in a laminated ferrimagnetic structure. The nonmagnetic intermediate layer 6 can be formed of a conductive nonmagnetic material such as Cu, Cr, Au, or Ag. In particular, it is preferably formed of Cu.
[0035]
The main magnetic layer 11a is formed using a magnetic material such as a CoFe alloy, a NiFe alloy, or a CoFeNi alloy. It is preferable that the thickness d1 of the main magnetic layer 11a is 15 ° or more and 50 ° or less. The nonmagnetic protective layer 16 can be formed of one or more of Ru, Rh, Pd, Ir, Os, Re, Cr, Cu, Pt, and Au. In particular, it is preferably formed of Cu.
[0036]
Next, a photoresist solution is applied on the non-magnetic protective layer 16 and exposed and developed to pattern the track width region (the track width region of the main magnetic layer 11a). A resist layer R shown in FIG. The resist layer R is a lift-off resist layer.
[0037]
After the formation of the resist layer R, ion milling is performed. In this ion milling step, the nonmagnetic protective layer 16, the main magnetic layer 11a, the nonmagnetic intermediate layer 6, the fixed magnetic layer 5, the antiferromagnetic layer 4, and the seed layer 3 exposed from both sides of the resist layer R in the track width direction are removed. Remove. As a result, portions of each layer outside the track width region indicated by dotted lines in FIG. 3 are removed, the dimension of the main magnetic layer 11a in the track width direction is restricted to the dimension T1, and both sides of the resist layer R in the track width direction are controlled. The lower gap layer 2 is exposed. Further, both ends in the track width direction of each layer from the seed layer 3 to the nonmagnetic protective layer 16 form an inclined surface (or a curved surface) that gradually widens in the track width direction from the upper layer to the lower layer. The arrow H direction shown in FIG. 3 is the ion milling direction.
[0038]
Subsequently, a nonmagnetic underlayer 7 and a hard bias layer 8 are continuously formed on the exposed lower gap layer 2 as shown in FIG. An ion beam sputtering method is used for film formation. The nonmagnetic underlayer 7 is formed not only on the lower gap layer 2 but also on an inclined surface (or a curved surface) formed by a side end in the track width direction of each layer from the seed layer 3 to the nonmagnetic protective layer 16. It is formed along an inclined surface (or a curved surface). The nonmagnetic underlayer 7 is preferably formed of a nonmagnetic material such as Cr, W, or Ti so that the coercive force of the hard bias layer 8 can be increased. The hard bias layer 8 is preferably formed of a magnetic material that does not significantly oxidize even in the atmosphere, for example, CoPt or CoCrPt. The magnetization of the hard bias layer 8 is performed when the GMR element 1 (or the thin-film magnetic head on which the GMR element 1 is mounted) shown in FIG. 1 is completed.
[0039]
After forming the hard bias layer 8, the resist layer R is removed by lift-off, and low energy ion milling is performed (FIG. 5). For the low energy ion milling of the present embodiment, for example, Ar ions accelerated at about 100 to 200 eV are used. This low-energy ion milling step has the effect of removing all the nonmagnetic protective layer 16 on the main magnetic layer 11a and flattening the upper surfaces of the main magnetic layer 11a and the hard bias layer 8. At this time, oxides and the like attached to the surface of the hard bias layer 8 are also removed. The arrow H direction shown in FIG. 5 is the ion milling direction, and the part shown by the dotted line in FIG. 5 is the part removed in this ion milling step.
[0040]
Subsequently, as shown in FIG. 6, the auxiliary magnetic layer 11b, the nonmagnetic layer 13, the second magnetic layer 12, and the protective layer 14 are continuously formed on the planarized main magnetic layer 11a and the hard bias layer 8. . Sputtering or vapor deposition is used for film formation. At this time, the auxiliary magnetic layer 11b, the nonmagnetic layer 13, and the second magnetic layer 12 are formed in the track width direction with a dimension T2 longer than the dimension T1 of the main magnetic layer 11a in the same direction. The auxiliary magnetic layer 11b is formed to have a thickness d1 ′ smaller than the thickness d1 of the main magnetic layer 11a, and the second magnetic layer 12 is formed to have a total thickness D1 (= the total thickness of the main magnetic layer 11a and the auxiliary magnetic layer 11b). d1 + d1 ′). The thickness d1 ′ of the auxiliary magnetic layer 11b is preferably 10 ° or more and 30 ° or less.
[0041]
The auxiliary magnetic layer 11b and the second magnetic layer 12 are preferably formed from the same magnetic material as the main magnetic layer 11a. The protective layer 14 functions as a stopper during RIE performed in a later step, and is preferably formed of a nonmagnetic material such as Ta or Cr.
[0042]
After the formation of the protective layer 14, annealing in a magnetic field is performed. The magnetic field direction at this time is the illustrated Y direction orthogonal to the track width direction. By the annealing in the magnetic field, an exchange coupling magnetic field can be generated between the antiferromagnetic layer 4 and the fixed magnetic layer 5, and the magnetization of the fixed magnetic layer 5 is firmly fixed in the Y direction. Further, anti-parallel coupling acting between the auxiliary magnetic layer 11b and the second magnetic layer 12, ferromagnetic parallel coupling acting between the auxiliary magnetic layer 11b and the main magnetic layer 11a, and an auxiliary magnetic layer 11b Ferromagnetic parallel coupling acting between the hard bias layer 8 and the hard bias layer 8 can be stabilized. The annealing in a magnetic field may be performed immediately after forming the nonmagnetic protective layer 16 in the step of FIG. 2 (between the steps of FIGS. 2 and 3).
[0043]
Subsequently, as shown in FIG. 7, an electrode lead layer E is formed on the protective layer 14, and a metal mask layer 15 is formed on the electrode lead layer E in a range other than the track width region by lift-off. In the present embodiment, since RIE is performed after the electrode lead layer E is formed, it is preferable to form the electrode lead layer E using a nonmagnetic conductive material such as Au or α-Ta. The metal mask layer 15 is preferably formed of a metal material having a low etching rate, which also functions as a RIE stopper. For example, Ta or Cr can be used.
[0044]
Then, RIE is performed using the metal mask layer 15 as a mask to remove the electrode lead layer E in the track width region. At this time, since the protective layer 14 in the track width region functions as an etching stopper, the RIE end timing can be appropriately controlled. That is, the RIE process is performed until the protection layer 14 is exposed. After performing the RIE process, the protective layer 14 in the track width region is removed by ion milling. However, since the protective layer 14 has a function of protecting the central portion 12a of the second magnetic layer 12 from oxidation, it is preferable to leave a part or all of the protective layer. Through the above steps, the GMR element 1 of FIG. 1 is obtained.
[0045]
As described above, in the present embodiment, the auxiliary magnetic layer 11b, the nonmagnetic layer 13, and the second magnetic layer 12 are provided so as to extend in the track width direction from the main magnetic layer 11a. In addition to the ferromagnetic parallel coupling between the auxiliary magnetic layer 11b and the second magnetic layer 12, the anti-parallel coupling between the auxiliary magnetic layer 11b and the second magnetic layer 12 occurs via the nonmagnetic layer 13. Ferromagnetic parallel coupling occurs with the bias layer 8. Thus, the extension 12b of the second magnetic layer 12 is firmly fixed in magnetization in the direction opposite to the magnetization direction of the hard bias layer 8 via the auxiliary magnetic layer 11b and the nonmagnetic layer 13. Therefore, the magnetization of the first magnetic layer 11 and the second magnetic layer 12 does not change with respect to the leakage magnetic field from the recording medium outside the track width region, so that the side reading can be prevented. Further, the disturbance of the magnetization of the second magnetic layer 12 can be reduced without the second magnetic layer 12 and the hard bias layer 8 directly facing each other, and the disturbance of the magnetization in the track width region can be reduced.
[0046]
FIG. 8 is a partial cross-sectional view showing the structure of the GMR element 20 according to the second embodiment of the present invention as viewed from a surface facing a recording medium. The second embodiment differs from the first embodiment in that a nonmagnetic protective layer 16 is interposed between the main magnetic layer 11a and the auxiliary magnetic layer 11b. In FIG. 8, components substantially the same as those in the first embodiment are denoted by the same reference numerals as those in FIG.
[0047]
The non-magnetic protective layer 16 has a thickness that causes an RKKY-like parallel coupling between the main magnetic layer 11a and the auxiliary magnetic layer 11b or a direct exchange coupling effect via a pinhole of the non-magnetic protective layer 16. are doing. The nonmagnetic protective layer 16 can be formed of one or more of Ru, Rh, Pd, Ir, Os, Re, Cr, Cu, Pt, and Au. For example, when the nonmagnetic protective layer 16 is formed of Ru or Cu, it is preferable that the film thickness be 6 mm or less.
[0048]
In the GMR element 20 of the second embodiment, the non-magnetic protective layer 16 is not entirely removed in the low energy ion milling step shown in FIG. 5, and the gap between the main magnetic layer 11a and the auxiliary magnetic layer 11b is formed as shown in FIG. The ion milling is completed when the thickness is reduced to a thickness that causes an RKKY-like parallel coupling or a direct exchange coupling effect via a pinhole of the nonmagnetic protective layer 16. Manufacturing steps other than the low energy ion milling step are the same as those in the first embodiment described above. When the nonmagnetic protective layer 16 is present on the main magnetic layer 11a, the surface of the main magnetic layer 11a is not roughened during the ion milling process, and the magnetization is disturbed by the milling damage (deterioration of soft magnetic characteristics). Can be avoided.
[0049]
In each of the above embodiments, the electrode lead layer E is formed by RIE, but the electrode lead layer E can also be formed by lift-off. When lift-off is used, the electrode lead layer E can be formed of a conductive material such as Cr, Ro, W, Ru, or Cu in addition to Au or α-Ta, and the metal mask layer 15 becomes unnecessary.
[0050]
FIGS. 10 and 12 show the results of calculating the magnetization distribution of the first magnetic layer and the second magnetic layer using the micromagnetic simulation method. Each simulation was performed under the following conditions.
Film thickness D2 of second magnetic layer = 16 (Å)
Hard bias layer thickness t = 400 (Å)
Residual magnetization Mr of hard bias layer × film thickness t = 37.7 (T · nm)
[FIG. 10]
Film thickness D1 of first magnetic layer = 35 (Å)
Main magnetic layer thickness d1 = 20 (Å)
Thickness d1 ′ of auxiliary magnetic layer = 15 (Å)
[FIG. 12]
Film thickness D1 of first magnetic layer = 24 (Å)
[0051]
【Example】
FIG. 10 shows a simulation result of calculating the magnetization distribution of the main magnetic layer 11a, the auxiliary magnetic layer 11b, and the second magnetic layer 12 of FIG. As described above, the dimension T2 of the auxiliary magnetic pole layer 11b and the second magnetic layer 12 in the track width direction is longer than the dimension T1 of the main magnetic layer 11a in the same direction. Referring to FIG. 10, although the magnetization is slightly inclined near the boundary between the central portion 12a and the extended portion 12b of the second magnetic layer 12, the magnetization of the main magnetic layer 11a is not so affected, and the track width region It can be seen that the magnetization is not disturbed inside. On the other hand, at both end portions in the track width direction, the antiparallel state is maintained between the second magnetic layer 12 and the auxiliary magnetic layer 11b, and it can be seen that disturbance due to the demagnetizing field and the bias magnetic field has not occurred.
[0052]
[Comparative example]
FIG. 12 shows a simulation result of calculating the magnetization distribution of the first magnetic layer 110 and the second magnetic layer 120 included in the conventional GMR element 1 ′ shown in FIG. In the conventional laminated ferrimagnetic free magnetic layer 100, the first magnetic layer 110 and the second magnetic layer 120 have the same dimension in the track width direction, and the first magnetic layer 110 and the second magnetic layer 120 have the same dimension in the track width direction. Hard bias layers 8 are provided directly on both sides. 12, it can be seen that the magnetization of the edge region α of the second magnetic layer 120 is tilted by the magnetic field from the hard bias layer 80, and the magnetization of the edge region α of the first magnetic layer 110 is disturbed. In such a magnetization distribution state, Barkhausen noise is likely to occur, and servo errors are also likely to occur.
[0053]
As is clear from FIGS. 10 and 12, the present GMR element 1 has less disturbance of the magnetization of the first magnetic layer and the second magnetic layer than the conventional GMR element 1 '. As a result, no servo error occurs, and the output sensitivity and the SN ratio of the GMR element can be improved.
[0054]
The present GMR element 1 is applicable not only to a reproducing thin-film magnetic head, but also to a recording / reproducing thin-film magnetic head in which a recording inductive head is further laminated on the reproducing thin-film magnetic head. It can also be used as various magnetic sensors.
[0055]
【The invention's effect】
According to the present invention, the auxiliary magnetic layer and the hard bias layer are ferromagnetically coupled in parallel, and the magnetization of the second magnetic layer is opposite to the magnetization direction of the hard bias layer via the auxiliary magnetic layer and the non-magnetic layer. , Side reading can be prevented. Further, according to the present invention, since the second magnetic layer and the hard bias layer do not directly face each other, the second magnetic layer does not receive a strong magnetic field from the hard bias layer, and the disturbance of magnetization in the edge region of the free magnetic layer is reduced. It is reduced.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view showing the structure of a giant magnetoresistive element (GMR element) according to a first embodiment of the present invention as viewed from a surface facing a recording medium.
FIG. 2 is a process chart of the method for manufacturing the GMR element shown in FIG.
FIG. 3 is a process drawing performed after the step shown in FIG. 2;
FIG. 4 is a process drawing performed after the step shown in FIG. 3;
FIG. 5 is a process drawing performed after the step shown in FIG. 4;
FIG. 6 is a process drawing performed after the step shown in FIG. 5;
FIG. 7 is a view showing a step performed after the step shown in FIG. 6;
FIG. 8 is a partial cross-sectional view showing the structure of a GMR element according to a second embodiment of the present invention, as viewed from a surface facing a recording medium.
9 is a process chart of the method for manufacturing the GMR element shown in FIG.
10 is a diagram showing a result of calculating a magnetization distribution of a free magnetic layer of the GMR element shown in FIG. 1 by using a micromagnetic simulation method.
FIG. 11 is a partial cross-sectional view showing the structure of a conventional GMR element including a laminated ferrimagnetic free magnetic layer as viewed from a surface facing a recording medium.
12 is a diagram illustrating a result of calculating a magnetization distribution of a free magnetic layer of the conventional GMR element illustrated in FIG. 11 using a micromagnetic simulation method.
[Explanation of symbols]
1 GMR element
2 Lower gap layer
3 Seed layer
4 Antiferromagnetic layer
5 Fixed magnetic layer
6 Non-magnetic intermediate layer
7 Non-magnetic underlayer
8 Hard bias layer
10 Free magnetic layer
11 1st magnetic layer
11a Main magnetic layer
11b Auxiliary magnetic layer
12 Second magnetic layer
12a Central part (central magnetic sensing part)
12b Extension
13 Non-magnetic layer
14 Protective layer
15 Metal mask layer
16 Non-magnetic protective layer
20 GMR element
E Electrode lead layer
R resist layer
H ion milling direction
Tw track width
T1 Dimension of main magnetic layer in track width direction
T2 Dimensions of the auxiliary magnetic layer, the non-magnetic layer, and the second magnetic layer in the track width direction
D1 Total thickness of first magnetic layer
d1 Thickness of main magnetic layer
d1 'Thickness of auxiliary magnetic layer
D2 Thickness of second magnetic layer
m1 Magnetic moment per unit area of the first magnetic layer
m2 Magnetic moment per unit area of the second magnetic layer
Magnetic moment per unit area of M-free magnetic layer
α edge area

Claims (24)

A laminated ferrimagnetic free magnetic layer having a first magnetic layer; a nonmagnetic layer formed on the first magnetic layer; and a second magnetic layer formed on the nonmagnetic layer; In a giant magnetoresistive element having a hard bias layer for aligning the magnetization direction,
The first magnetic layer is formed so as to correspond to a track width region, and has a main magnetic layer in contact with the hard bias layer at both ends in the track width direction, and straddles the main magnetic layer and the hard bias layer. And a total thickness of the main magnetic layer and the auxiliary magnetic layer is formed to be larger than the thickness of the second magnetic layer,
The auxiliary magnetic layer, the non-magnetic layer, and the second magnetic layer are formed such that the dimension in the track width direction is longer than the dimension of the main magnetic layer in the same direction,
The giant magnetoresistive element, wherein the nonmagnetic layer is formed to a thickness that causes RKKY antiparallel coupling between the auxiliary magnetic pole layer and the second magnetic layer. 2. The giant magnetoresistance effect element according to claim 1, wherein said auxiliary magnetic layer is formed with a smaller thickness than said main magnetic layer. 3. The giant magnetoresistance effect element according to claim 2, wherein said main magnetic layer is formed with a thickness of 15 to 50 degrees, and said auxiliary magnetic layer is formed with a thickness of 10 to 30 degrees. 4. The non-magnetic protective layer according to claim 1, wherein the non-magnetic protective layer is formed of a conductive non-magnetic material between the main magnetic layer and the auxiliary magnetic layer. 5. The thickness of the non-magnetic protective layer causes an RKKY-like parallel coupling between the main magnetic layer and the auxiliary magnetic layer or a direct exchange interaction via a pinhole of the non-magnetic protective layer. A giant magnetoresistive element whose film thickness is to be reduced. 5. The giant magnetoresistance effect element according to claim 4, wherein said nonmagnetic protective layer has a thickness of 6 mm or less. 6. The giant magnetoresistive element according to claim 4, wherein the nonmagnetic protective layer is at least one of Ru, Rh, Pd, Ir, Os, Re, Cr, Cu, Pt, and Au. A giant magnetoresistive element formed of. 7. The giant magnetoresistive element according to claim 1, wherein said first magnetic layer and said second magnetic layer are formed of one of CoFe, NiFe, and CoFeNi. element. 8. The giant magnetoresistive element according to claim 1, wherein said hard bias layer is made of CoPt or CoCrPt. 9. The giant magnetoresistive element according to claim 1, wherein the nonmagnetic layer is any one of Ru, Rh, Pd, Ir, Os, Re, Cr, Cu, Pt, and Au. 10. A giant magnetoresistive element formed of one or more species. 9. The giant magnetoresistance effect element according to claim 1, wherein said nonmagnetic layer is formed of Ru, and has a thickness of 6 to 15 degrees. 9. The giant magnetoresistive element according to claim 1, wherein said nonmagnetic layer is formed of Cu and has a thickness of 7 to 12 degrees. (A) forming a laminated body having an antiferromagnetic layer, a fixed magnetic layer, a nonmagnetic intermediate layer, a main magnetic layer of a first magnetic layer, and a nonmagnetic protective layer on a substrate;
(B) forming a resist layer on a track width region of the laminate;
(C) removing at least the non-magnetic protective layer, the main magnetic layer, and the non-magnetic intermediate layer of the laminate exposed from both sides in the track width direction of the resist layer, and forming a hard bias layer on the removed portion And removing the resist layer;
(D) removing all non-magnetic protective layers on the main magnetic layer;
(E) laminating an auxiliary magnetic layer, a non-magnetic layer, and a second magnetic layer of the first magnetic layer on the main magnetic layer and the hard bias layer,
In the step (e), the nonmagnetic layer is formed with a thickness that causes RKKY-like antiparallel coupling between the auxiliary magnetic layer and the second magnetic layer. The auxiliary magnetic layer and the auxiliary magnetic layer are formed to have a thickness smaller than the total thickness of the auxiliary magnetic layer, and the auxiliary magnetic layer, the non-magnetic layer, and the second magnetic layer are dimensioned in the track width direction. A method for manufacturing a giant magnetoresistive element, wherein the element is formed to be longer than the dimension in the same direction. 13. The method for manufacturing a giant magnetoresistive element according to claim 12, wherein the auxiliary magnetic layer is formed with a smaller thickness than the main magnetic layer. 14. The method for manufacturing a giant magnetoresistive element according to claim 13, wherein the main magnetic layer is formed with a thickness of 15 to 50 degrees, and the auxiliary magnetic layer is formed with a thickness of 10 to 30 degrees. Device manufacturing method. 15. The method of manufacturing a giant magnetoresistance effect element according to claim 12, wherein, instead of the step (d), (f) the non-magnetic protective layer on the main magnetic layer is replaced with the main magnetic layer. 16. Production of a giant magnetoresistive element having a step of cutting down to a thickness that causes an RKKY-like parallel coupling between a layer and the auxiliary magnetic layer or a direct exchange coupling effect via a pinhole of the nonmagnetic protective layer. Method. 16. The method for manufacturing a giant magnetoresistive element according to claim 15, wherein the nonmagnetic protective layer has a thickness of 6 mm or less. 17. The method for manufacturing a giant magnetoresistance effect element according to claim 12, wherein in the step (d) or the step (f), the non-magnetic protective layer is cut using low energy ion milling. A method for manufacturing a giant magnetoresistive element. The method for manufacturing a giant magnetoresistive element according to any one of claims 12 to 17, wherein the nonmagnetic protective layer is made of one of Ru, Rh, Pd, Ir, Os, Re, Cr, Cu, Pt, and Au. A method for manufacturing a giant magnetoresistive element formed of one or more of them. 19. The method for manufacturing a giant magnetoresistive element according to claim 12, wherein after the step (e), (g) annealing is performed in a magnetic field to form the antiferromagnetic layer and the fixed magnetic layer. A method for manufacturing a giant magnetoresistive element, comprising the step of generating an exchange coupling magnetic field between the elements. 20. The method for manufacturing a giant magnetoresistance effect element according to claim 12, wherein the nonmagnetic layer is any one of Ru, Rh, Pd, Ir, Os, Re, Cr, Cu, Pt, and Au. Or a method for manufacturing a giant magnetoresistive element formed of one or more types. 21. The method of manufacturing a giant magnetoresistive element according to claim 12, wherein the nonmagnetic layer is formed of Ru, and has a thickness of 6 to 15 degrees. Method. 21. The method of manufacturing a giant magnetoresistive element according to claim 12, wherein the nonmagnetic layer is formed of Cu, and has a thickness of 7 to 12 degrees. Method. The method for manufacturing a giant magnetoresistive element according to any one of claims 12 to 22, wherein the hard bias layer is formed of CoPt or CoCrPt. 24. The method of manufacturing a giant magnetoresistance effect element according to claim 12, wherein the main magnetic layer and the auxiliary magnetic layer of the first magnetic layer and the second magnetic layer are made of CoFe, NiFe, CoFeNi. A method for manufacturing a giant magnetoresistive element formed of any of the above.

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