JP4360958B2 - Magnetoresistive element, thin film magnetic head, head gimbal assembly, head arm assembly, and magnetic disk apparatus - Google Patents

Description

  The present invention relates to a magnetoresistive effect element that exhibits a giant magnetoresistive effect, and a thin film magnetic head, a head gimbal assembly, a head arm assembly, and a magnetic disk device having the magnetoresistive effect element mounted thereon. The present invention relates to a configured magnetoresistive effect element, and a thin film magnetic head, a head gimbal assembly, a head arm assembly, and a magnetic disk apparatus including the magnetoresistive element.

  Conventionally, in reproducing information on a magnetic recording medium such as a hard disk, a thin film magnetic head including an MR element exhibiting a magnetoresistive (MR) effect has been widely used. In recent years, the recording density of magnetic recording media has been increasing, and a thin film magnetic head using a giant magnetoresistive element (GMR element) exhibiting a giant magnetoresistive (GMR: Giant Magnetoresistive) effect is common. An example of such a GMR element is a spin valve (SV) type GMR element.

  This SV type GMR element includes a magnetic layer (magnetization pinned layer) in which the magnetization direction is fixed in a fixed direction via a nonmagnetic intermediate layer, and a magnetic layer in which the magnetization direction changes in response to a signal magnetic field from the outside. In the reproduction operation, for example, a sense current flows in the in-plane direction of the stacked layer. Such a GMR element is particularly called a CIP (Current in Plane) -GMR element. In this case, the electric resistance (that is, the voltage) changes when a sense current is passed according to the relative angle of the magnetization direction in the two magnetic layers (magnetization pinned layer and magnetization free layer) of the SV film.

  Recently, a thin film magnetic head having a CPP (Current Perpendicular to the Plane) -GMR element configured to allow a sense current to flow in the direction of stacking of the SV film during a reproducing operation in order to cope with further improvement in recording density. Development is underway. Such a CPP-GMR element generally includes an SV film and a pair of magnetic domain control films disposed so as to face each other with the SV film sandwiched in a direction corresponding to the reproduction track width direction via an insulating film. And upper and lower electrodes formed so as to sandwich the SV film and the pair of magnetic domain control films along the stacking direction. The upper and lower electrodes also serve as upper and lower shield films. The CPP-GMR element having such a configuration has an advantage that a high output can be obtained as compared with the CIP-GMR element when the dimension in the reproduction track width direction is reduced. Specifically, in the CIP-GMR element, since the sense current flows in the in-plane direction, the magnetosensitive part through which the sense current passes becomes minute as the size in the reproduction track width direction is narrowed, and the voltage change amount is small. On the other hand, in the case of a CPP-GMR element, a sense current flows in the stacking direction, so that there is little influence on the amount of voltage change due to narrowing in the reproduction track width direction. From such a background, the CPP-GMR element is expected to be capable of dealing with further improvement in recording density.

  In particular, the magnetization fixed layer has a three-layer structure having two ferromagnetic films (first and second magnetization fixed films) having magnetization directions fixed in antiparallel to each other and a nonmagnetic film provided therebetween. In the case of a synthetic type, the net moment is reduced and the magnetization direction becomes difficult to rotate even when an external magnetic field is applied, and exchange coupling between two ferromagnetic films occurs, so that the magnetization direction is stabilized. In addition, since the net moment is reduced, the static magnetic field in the magnetic head is reduced, and the symmetry of the output waveform is improved. A synthetic CPP-GMR element having such a synthetic magnetization pinned layer can exhibit excellent performance as a means for reproducing magnetic recording information due to its structural characteristics.

As a prior art related to a CPP-GMR element, for example, a structure in which a magnetization free layer or a magnetization fixed layer has a multilayer structure in which a ferromagnetic film and a nonmagnetic film are alternately laminated is disclosed (for example, see Patent Document 1). .) With such a multilayer structure, the spin-dependent scattering effect is enhanced and a large output is obtained. In addition, a multi-structure (specifically, “a magnetic pinned layer having a synthetic type) in which at least one of the two pinned magnetic films constituting the magnetic pinned layer includes an intermediate layer made of a nickel iron alloy (NiFe)”. For example, Patent Document 2 discloses a CIP-GMR element having a structure of “cobalt (Co) / NiFe / cobalt (Co)”. In this case, the ferromagnetic coupling magnetic field between the free layer and the magnetization pinned layer can be reduced, and a high magnetoresistance change rate can be obtained. Furthermore, a material having a negative bulk scattering coefficient β is used for at least one of the free layer and the pinned magnetic layer, and a material having a negative interface scattering coefficient γ is sandwiched between the free layer and the pinned magnetic layer. A synthetic CPP-GMR element used for a magnetic intermediate layer is disclosed in Patent Document 3, for example. Such a configuration aims to obtain a larger magnetoresistance change rate.
JP 2002-092826 A JP 2001-052317 A JP 2003-298142 A

  However, since the conventional synthetic CPP-GMR element has a structure in which the magnetizations of the first and second magnetization fixed layers are coupled antiparallel to each other, the net moment is reduced and the magnetization direction is stabilized. On the other hand, since a current flows in the stacking direction with respect to the SV film, there is a problem that a part of the resistance change amount is lost due to the structural feature. . That is, the resistance change amount (voltage change amount) due to the GMR effect generated between the first magnetization pinned film and the magnetization free layer, and the second magnetization pinion showing the magnetization direction opposite to that of the first magnetization pinned film. A resistance change amount (voltage change amount) due to the GMR effect generated between the film and the magnetization free layer cancels a part of each other.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a magnetoresistive element capable of obtaining a larger amount of resistance change and corresponding to a higher recording density, a thin film magnetic head equipped with the magnetoresistive element, and a head gimbal. To provide an assembly, a head arm assembly, and a magnetic disk device.

Magnetoresistive effect element of the present invention show a first magnetization pinned film exhibiting anchored magnetization direction in a predetermined direction, the magnetization direction is fixed in the opposite direction to the magnetization direction of the first magnetization pinned layer And a magnetization pinned layer having a second magnetization pinned film exhibiting a bulk scattering coefficient of 0.25 or less and a first magnetization pinned film on the opposite side of the second magnetization pinned film, A magnetization free layer showing a magnetization direction that changes accordingly, and a current path through which a sense current flows in a direction orthogonal to the laminated surface with respect to the magnetization pinned layer and the magnetization free layer are configured. Further, the thin film magnetic head of the present invention are those having a magnetoresistive element described above, f head gimbal assembly of the present invention, a magnetic head slider such a thin film magnetic head is provided on one side surface, The magnetic head slider has a suspension attached to one end. F head arm assembly of the present invention has to include an arm for supporting the above head gimbal assembly, the other end of the suspension. Furthermore, magnetic disk device of the present invention has as comprising a magnetic recording medium, and said head arm assembly.

Magnetoresistive effect element of the present invention, thin-film magnetic head, head gimbal assembly, the head arm assembly and a magnetic disk apparatus, the second magnetization pinned layer farther from the magnetization free layer of the first and second magnetization pinned layer Is configured to exhibit a bulk scattering coefficient of 0.25 or less, so that the bulk scattering by the second magnetization pinned film acting so as to cancel out the resistance change amount generated between the magnetization free layer and the first pinned film. The effect is suppressed.

Magnetoresistive effect element of the present invention, thin-film magnetic head, head gimbal assembly, the head arm assembly and a magnetic disk device, that the second magnetization pinned film is particularly configured to exhibit bulk scattering coefficient of 0.20 or less desirable.

In the magnetoresistive element, the thin film magnetic head, the head gimbal assembly, the head arm assembly, and the magnetic disk device of the present invention, the second magnetization pinned film in the magnetization pinned layer includes at least one of tantalum, chromium, and vanadium. It is good to do so.

Magnetoresistive effect element of the present invention, thin-film magnetic head, head gimbal assembly, the head arm assembly and a magnetic disk device, the content of tantalum, 11.8 atomic percent 1 atom% or more of the second magnetization pinned layer The chromium content is 13 atomic percent or more and 26.5 atomic percent or less of the second magnetization pinned film, and the vanadium content is 13 atom percent of the second magnetization pinned film. It is desirable that it is 29.4 atomic percent or less. The second magnetization pinned film can be made of a material containing at least one of iron (Fe), cobalt (Co), nickel (Ni), and manganese (Mn). In that case, the composition ratio of cobalt and iron is, for example, 9: 1.

Magnetoresistive effect element of the present invention, thin-film magnetic head, head gimbal assembly, the head arm assembly and a magnetic disk apparatus, the first and second magnetization pinned film, are exchange-coupled to each other via a nonmagnetic layer Is desirable. Furthermore, it is preferable to have an antiferromagnetic layer that fixes the magnetization direction of the second magnetization pinned film on the side opposite to the first magnetization pinned film of the second magnetization pinned film. Furthermore, an intermediate layer is provided between the magnetization pinned layer and the magnetization free layer. Further, the current path is constituted by first and second electrode layers arranged to face each other so as to sandwich the magnetization fixed layer and the magnetization free layer in a direction orthogonal to the laminated surface.

Magnetoresistive effect element of the present invention, thin-film magnetic head, head gimbal assembly, according to the head arm assembly and a magnetic disk device, a first magnetization pinned film exhibiting anchored magnetization direction in a predetermined direction, the first A magnetization pinned layer including a second magnetization pinned film showing a magnetization direction pinned in a direction opposite to the magnetization direction of the magnetization pinned film and having a bulk scattering coefficient of 0.25 or less; and A magnetization free layer provided on the opposite side of the second magnetization pinned film and exhibiting a magnetization direction that changes in response to an external magnetic field, and a sense current in a direction perpendicular to the stack surface with respect to the magnetization pinned layer and the magnetization free layer Since a current path through which a current flows is provided, it is possible to suppress a decrease in resistance change caused by the second magnetization pinned film. Therefore, the resistance change rate is improved by increasing the overall resistance change amount, and it becomes possible to cope with a higher recording density. In particular, when the second magnetization pinned film is configured so as to exhibit a bulk scattering coefficient of 0.20 or less, a larger resistance change amount can be obtained, and it is possible to cope with a higher recording density.

  According to the magnetoresistive effect element, the thin film magnetic head, the head gimbal assembly, the head arm assembly, and the magnetic disk device according to the second aspect of the present invention, the first magnetization pinned film showing the magnetization direction fixed in a certain direction; A second magnetization pinned which shows a magnetization direction fixed opposite to the magnetization direction of the first magnetization pinned film and contains at least one of tantalum (Ta), chromium (Cr) and vanadium (V) A magnetization pinned layer including a film, a magnetization free layer provided on the opposite side of the first magnetization pinned film to the second magnetization pinned film, and showing a magnetization direction that changes according to an external magnetic field, and a magnetization pinned layer In addition, since the magnetic free layer is provided with a current path through which a sense current flows in a direction orthogonal to the laminated surface, it is possible to suppress a decrease in the resistance change amount caused by the second magnetization pinned film. Therefore, the resistance change rate is improved by increasing the overall resistance change amount, and it becomes possible to cope with a higher recording density.

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

  First, referring to FIG. 1 to FIG. 5, the configurations of a magnetoresistive effect element according to an embodiment of the present invention, and a thin film magnetic head, a head gimbal assembly, a head arm assembly, and a magnetic disk device having the same are described below. Explained.

  FIG. 1 is a perspective view showing the internal configuration of the magnetic disk apparatus according to the present embodiment. As shown in FIG. 1, the magnetic disk device includes, for example, a magnetic recording medium 200 as a magnetic recording medium on which information is recorded, and information stored in the magnetic recording medium 200. A head arm assembly (HAA) 300 for recording and reproducing the information is provided. The HAA 300 includes a head gimbal assembly (HGA) 2, an arm 3 that supports the base of the HGA 2, and a drive unit 4 as a power source that rotates the arm 3. The HGA 2 includes a magnetic head slider (hereinafter simply referred to as “slider”) 2A having a thin film magnetic head 1 (described later) according to the present embodiment provided on one side surface, and a suspension having the slider 2A attached to one end. 2B. The other end of the suspension 2B (the end opposite to the slider 2A) is supported by the arm 3. The arm 3 is configured to be rotatable via a bearing 6 with a fixed shaft 5 fixed to the housing 100 as a central axis. The drive part 4 consists of a voice coil motor etc., for example. In general, the magnetic disk apparatus includes a plurality of magnetic recording media 200 as shown in FIG. 1, and sliders 2A are provided corresponding to the recording surfaces (front and back surfaces) of each magnetic recording medium 200, respectively. It has come to be. Each slider 2A can move in a direction (X direction) across the reproduction track in a plane parallel to the recording surface of each magnetic recording medium 200. On the other hand, the magnetic recording medium 200 rotates about a spindle motor 7 fixed to the housing 100 in a direction substantially orthogonal to the X direction. Information is recorded on the magnetic recording medium 200 by the rotation of the magnetic recording medium 200 and the movement of the slider 2A, or the recorded information is read out.

FIG. 2 shows the configuration of the slider 2A shown in FIG. The slider 2A has a block-shaped base 8 made of, for example, Altic (Al ₂ O ₃ · TiC). The base 8 is formed in, for example, a substantially hexahedron shape, and is disposed so that one surface thereof is close to and faces the recording surface of the magnetic recording medium 200. A surface facing the recording surface of the magnetic recording medium 200 is a recording medium facing surface (also referred to as an air bearing surface) 9, and air generated between the recording surface and the recording medium facing surface 9 when the magnetic recording medium 200 rotates. Due to the lift caused by the flow, the slider 2 </ b> A floats from the recording surface along the direction facing the recording surface (Y direction) so that a certain gap is formed between the recording medium facing surface 9 and the magnetic recording medium 200. It has become. A thin film magnetic head 1 is provided on one side of the substrate 8 with respect to the recording medium facing surface 9.

  FIG. 3 is an exploded perspective view showing the configuration of the thin film magnetic head 1. FIG. 4 is a cross-sectional view illustrating the structure in the direction of the arrows along the line IV-IV shown in FIG. As shown in FIGS. 3 and 4, the thin film magnetic head 1 includes a reproducing head unit 1 </ b> A for reproducing magnetic information recorded on the magnetic recording medium 200, and a recording for recording magnetic information on a recording track of the magnetic recording medium 200. The head portion 1B is integrally formed.

As shown in FIGS. 3 and 4, the reproducing head portion 1A includes a magnetoresistive effect element having a CPP (Current Perpendicular to the Plane) -GMR (Giant Magnetoresistive) structure in which a sense current flows in the stacking direction. (Hereinafter referred to as MR element) 10. Specifically, on the surface exposed to the recording medium facing surface 9, for example, the lower electrode 11, the MR film 20 and the pair of magnetic domain control films 12, the insulating film 13, and the upper electrode 14 are formed on the substrate 8. The structure is laminated in order. Although not shown in FIGS. 3 and 4, as will be described later, a pair of insulating films is provided between the pair of magnetic domain control films 12 and the MR film 20 and between the pair of magnetic domain control films 12 and the lower electrode 11. 15 is provided. The insulating film 13 is provided so as to surround the periphery of the MR film 20 excluding the recording medium facing surface 9 in the XY plane. Specifically, the insulating film 13 faces the MR film 20 across the X direction. It consists of two parts: a part 13A (see FIG. 3) and a second part 13B (see FIG. 4) occupying a region opposite to the recording medium facing surface 9 with the MR film 20 in between. For example, the lower electrode 11 and the upper electrode 14 each have a thickness of 1 μm to 3 μm and are made of a magnetic metal material such as nickel iron alloy (NiFe). The lower electrode 11 and the upper electrode 14 face each other with the MR film 20 sandwiched in the stacking direction (Z direction), and function so that the MR film 20 is not affected by an unnecessary magnetic field. Further, the lower electrode 11 is connected to the pad 11P, and the upper electrode 14 is connected to the pad 14P, and also has a function as a current path through which current flows in the stacking direction (Z direction) with respect to the MR film 20. . The MR film 20 has a synthetic spin valve (SV) structure in which a number of metal films containing a magnetic material are stacked, and has a function of reading magnetic information recorded on the magnetic recording medium 200. The pair of magnetic domain control films 12 are disposed so as to face each other with the MR film 20 interposed therebetween in a direction (X direction) corresponding to the reproduction track width direction of the magnetic recording medium 200. In the reproducing head unit 1A having such a configuration, recorded information is read by utilizing the fact that the electrical resistance of the MR film 20 changes according to the signal magnetic field from the magnetic recording medium 200. The detailed configuration of the MR film 20 will be described later. The insulating film 13 and the insulating layer 16 each have a thickness of 10 nm to 100 nm, for example, and are made of an insulating material such as aluminum oxide (Al ₂ O ₃ ) or aluminum nitride (AlN). The insulating film 13 is mainly for electrically insulating the lower electrode 11 and the upper electrode 14, and the insulating layer 16 is for electrically insulating the reproducing head portion 1A and the recording head portion 1B. It is.

  Next, the configuration of the recording head unit 1B will be described. As shown in FIGS. 3 and 4, the recording head portion 1B is formed on the insulating layer 16 of the reproducing head portion 1A, and includes a lower magnetic pole 41, a recording gap layer 42, a pole tip 43, a coil 44, It has an insulating layer 45, a connecting portion 46 and an upper magnetic pole 47.

The lower magnetic pole 41 is made of a magnetic material such as NiFe and is formed on the insulating layer 16. The recording gap layer 42 is made of an insulating material such as Al ₂ O ₃ and is formed on the lower magnetic pole 41. The recording gap layer 42 has an opening 42A for forming a magnetic path at a position corresponding to the center of the coil 44 in the XY plane. On the recording gap layer 42, a pole tip 43, an insulating layer 45, and a connecting portion 46 are formed in the same plane in this order from the recording medium facing surface 9 side. A coil 44 is embedded in the insulating layer 45. The coil 44 is formed on the recording gap layer 42 with the opening 42A as the center, and is made of, for example, copper (Cu) or gold (Au). Both terminals of the coil 44 are connected to the electrodes 44S and 44E, respectively. The upper magnetic pole 47 is made of, for example, a magnetic material such as NiFe, and is formed on the recording gap layer 42, the pole tip 43, the insulating layer 45, and the connecting portion 46 (see FIG. 4). The upper magnetic pole 47 is in contact with the lower magnetic pole 41 through the opening 42A and is magnetically coupled. Although not shown, an overcoat layer made of Al ₂ O ₃ or the like is formed so as to cover the entire top surface of the recording head portion 1B.

  The recording head unit 1B having such a configuration generates a magnetic flux inside a magnetic path mainly constituted by the lower magnetic pole 41 and the upper magnetic pole 47 by a current flowing through the coil 44, and a signal generated in the vicinity of the recording gap layer 42. Information is recorded by magnetizing the magnetic recording medium 200 with a magnetic field.

  Next, a detailed configuration of the MR element 10 in the thin film magnetic head 1 of the present embodiment will be described with reference to FIG. 5 is a cross-sectional view showing the structure of the MR element 10 as viewed from the direction of the arrow V in FIG.

As shown in FIG. 5, the MR element 10 includes, in order from the lower magnetic pole 11 side, an underlayer 21, an antiferromagnetic layer 22, a magnetization pinned layer 23, an intermediate layer 24, a magnetization free layer 25, The MR film 20 is laminated with the protective layer 26. The underlayer (also referred to as a buffer layer) 21 is made of, for example, tantalum (Ta) having a thickness of 5 nm, and the like, and includes an antiferromagnetic layer 22 and a magnetization pinned layer 23 (more precisely, a second magnetization pinned to be described later). It functions so that exchange coupling with the membrane 233) can be performed satisfactorily. The antiferromagnetic layer 22 is made of a material exhibiting antiferromagnetism, such as platinum manganese alloy (PtMn) or iridium manganese alloy (IrMn), and has a thickness of 7 nm to 15 nm, for example. The antiferromagnetic layer 22 functions as a so-called pinning layer that fixes the magnetization direction of the magnetization pinned layer 23.

The magnetization pinned layer 23 has a three-layer structure called a so-called synthetic structure, and includes a first magnetization pinned film 231, a second magnetization pinned film 233, and the first and second magnetization pinned films 231 and 233. And a non-magnetic film 232 provided therebetween. More specifically, the first magnetization pinned film 231 shows a magnetization direction J231 fixed in a certain direction, and has a thickness of 3 nm to 4 nm, for example. The second magnetization pinned film 233 has a magnetization direction J233 fixed in a direction opposite to the magnetization direction J231 and a bulk scattering coefficient β of 0.25 or less, and has a thickness of 3 nm, for example. Further, the nonmagnetic film 232 is made of a nonmagnetic metal material such as copper, gold, ruthenium (Ru), rhodium (Rh), or iridium (Ir), and has a thickness of, for example, 0.8 nm. Here, the second magnetization fixed film 233 is formed on the opposite side of the magnetization free layer 25 with the first magnetization fixed film 231 interposed therebetween. The first and second magnetization pinned films 231 and 233 are in antiferromagnetic exchange coupling with each other via the nonmagnetic film 232, and their magnetization directions J231 and J233 are pinned by the antiferromagnetic layer 22. ing. Here, the bulk scattering coefficient β of the second magnetization pinned film 233 is particularly preferably 0.20 or less.

The second magnetization pinned film 233 is configured using, as a base material, a ferromagnetic material including at least one of, for example, iron (Fe), cobalt (Co), nickel (Ni), and manganese (Mn). A preferred composition ratio of cobalt and iron is 9: 1. Furthermore, the second magnetization pinned film 233 is configured to include at least one of tantalum (Ta), chromium (Cr), and vanadium (V) as an additive substance, for example. In that case, the tantalum content is desirably 1 atomic percent (hereinafter referred to as “at%”) or more and 11.8 at% or less of the entire second magnetization pinned film 233. The chromium content is 13 at% or more and 26.5 at% or less of the entire second magnetization pinned film 233, and the vanadium content is 13 at% or more and 29.4 at% of the entire second pinned film 233. The following is desirable. The significance of these numerical ranges will be described in the examples described later.

  The second magnetization pinned film 233 may have a single layer structure or a laminated structure. For example, it may be a single layer made of components such as cobalt iron tantalum alloy (CoFeTa), cobalt iron nickel chromium alloy (CoFeNiCr), cobalt iron chromium alloy (CoFeCr) or cobalt iron vanadium alloy (CoFeV), or CoFe, Ta A single layer composed of different components such as NiCr, FeCr or FeV may have a laminated structure (for example, “CoFe / Ta”, “CoFe / FeCr”, “CoFe / FeV”, etc.).

  Similar to the second magnetization pinned film 233, the first magnetization pinned layer 231 may have a single layer structure or a multilayer structure. For example, a single layer made of CoFe or a laminated structure in which CoFe and copper are alternately and repeatedly laminated may be used. As will be described later, since a magnetoresistive effect can be expected even at the interface between a magnetic material and a non-magnetic material, the amount of resistance change due to the magnetoresistive effect is improved by forming a multilayer structure such as “CoFe / Cu” as described above. There is expected.

The intermediate layer 24 is made of a nonmagnetic metal material having a high electrical conductivity (small electrical resistance) such as copper or gold, and has a thickness of 3.2 nm, for example. The intermediate layer 24 mainly functions to disconnect the magnetic coupling between the magnetization free layer 25 and the magnetization pinned layer 23 (first magnetization pinned film 231). The sense current that flows during the read operation passes through the first magnetization pinned film 231 from the lower electrode 11 and then passes through the intermediate layer 24 to reach the magnetization free layer 25. At this time, since it is necessary to minimize the scattering received by the sense current, it is preferable that the intermediate layer 24 is made of the above-described material having a small electric resistance. The magnetization free layer 25 has a magnetization direction that changes in response to an external magnetic field, and is formed on the opposite side of the second magnetization pinned film 233 with the first magnetization pinned film 231 interposed therebetween. The magnetization free layer 25 has a three-layer structure in which a nonmagnetic film 252 made of copper or the like is formed between ferromagnetic films 251 and 253 made of, for example, cobalt iron alloy (CoFe) or nickel iron alloy (NiFe). ing. The thickness of the ferromagnetic films 251 and 253 is, for example, 1.5 nm (15 Å), and the thickness of the nonmagnetic film 252 is, for example, 0.3 nm (3 Å). The ferromagnetic films 251 and 253 in the magnetization free layer 25 exhibit a magnetization direction that changes in accordance with the direction and magnitude of an external magnetic field (in this embodiment, a signal magnetic field from the magnetic recording medium 200). The magnetization free layer 25 may have a single layer structure made of a ferromagnetic material such as a cobalt iron alloy (CoFe) or a nickel iron alloy (NiFe). Furthermore, the protective layer 26 is made of, for example, copper or tantalum having a thickness of 1 nm to 5 nm, and functions to protect the MR element 10 after film formation in the manufacturing process.

The magnetic domain control film 12 is composed of a base layer 121 formed on the lower electrode 11 via an insulating film 15 and a magnetic domain control layer 122 formed thereon. The magnetic domain control film 12 is disposed so as to face the MR film 20 in the X direction (direction corresponding to the reproduction track width), and applies a longitudinal bias magnetic field to the magnetization free layer 25. More specifically, the underlayer 121 is made of, for example, chromium titanium alloy (CrTi) or tantalum (Ta), and functions to improve the growth of the magnetic domain control layer 122 in the manufacturing process. The magnetic domain control layer 122 is made of, for example, cobalt platinum alloy (CoPt) or the like, and functions to promote the formation of a single magnetic domain in the magnetization free layer 25 and suppress the generation of Barkhausen noise. Here, a pair of insulating films 15 are provided between the pair of magnetic domain control films 12 and the MR film 20 and between the pair of magnetic domain control films 12 and the lower magnetic pole 11. The pair of insulating films 15 is made of, for example, an electrically insulating material such as Al ₂ O ₃ or AlN, and is formed so as to continuously cover from both end surfaces S20 of the MR film 20 to the upper surface S11 of the lower magnetic pole 11. ing. Therefore, the pair of magnetic domain control films 12, the MR film 20, and the lower magnetic pole 11 are electrically insulated.

  As shown in FIG. 5, the lower and upper electrodes 11 and 14 are arranged to face each other so as to sandwich the MR film 20 having the above configuration in a direction (Z direction) perpendicular to the laminated surface. When reading the magnetic information of the medium 200, it functions as a current path for flowing a sense current in the Z direction with respect to the MR film 20.

  Next, the reproducing operation of the MR element 10 and the thin film magnetic head 1 configured as described above will be described with reference to FIGS.

  In the thin film magnetic head 1, information recorded on the magnetic recording medium 200 is read by the reproducing head unit 1A. When reading recorded information, the recording medium facing surface 9 faces the recording surface of the magnetic recording medium 200, and in this state, the signal magnetic field from the magnetic recording medium 200 reaches the MR element 10. At this time, a sense current is passed through the MR film 20 in advance in the stacking direction (Z direction) via the lower electrode 11 and the upper electrode 14. That is, a sense current flows through the MR film 20 in the order of the underlayer 21, the antiferromagnetic layer 22, the magnetization pinned layer 23, the intermediate layer 24, the magnetization free layer 25, and the protective layer 26, or vice versa. ing. In the MR film 20, a magnetization free layer 25 whose magnetization direction is changed by a signal magnetic field and a magnetization fixed layer 23 whose magnetization direction is fixed to a substantially constant direction by the antiferromagnetic layer 22 and not affected by the signal magnetic field. Thus, the relative magnetization direction changes. As a result, a change in spin-dependent scattering of conduction electrons occurs, and a change occurs in the electrical resistance of the MR film 20. This change in electrical resistance causes a change in output voltage, and the recording information of the magnetic recording medium 200 is read by detecting this change in current. Further, by providing the pair of insulating films 15, the sense current flowing between the lower shield 11 and the upper shield 14 is less likely to leak into the pair of magnetic domain control films 12. That is, since the sense current passes through the MR film 20 without being spread in the X direction, the resistance change of the sense current due to the change in the magnetization direction of the magnetization free layer 25 is detected with higher sensitivity. can do. In FIG. 5, the pair of insulating films 15 covers the pair of end surfaces S20 of the MR film 20 and covers the upper surface S11 of the lower magnetic pole 11 so as to extend in the X direction. What is necessary is just to cover S20B, and the said effect is acquired by this.

  Next, the operation of the MR element 10 of the present embodiment will be described.

As described above, in the conventional synthetic CPP-GMR element, the resistance change generated between the first magnetization fixed film and the magnetization free layer cannot be sufficiently utilized, and an improvement thereof is desired. It was. The factor and the solution method will be described with reference to FIGS.

As already described, in the CPP-GMR element, a sense current flows in a direction perpendicular to the laminated surface. Therefore, with respect to the MR element having the formation area A as shown in FIG. 6 and the thickness t, the voltage change ΔV when the sense current I flows in the direction (−Z direction) perpendicular to the laminated surface is It depends on the product of the specific resistance change Δρ and the thickness t, ie, the volume of the object. Therefore,
ΔV = Δρ · t · J (1)
It is expressed. Here, “J” is the current density. Expression (1) can be expressed as Expression (2) using the MR element formation area A and the resistance change amount ΔR per unit area.
ΔV = A ・ ΔR ・ J (2)
From equation (2), it can be seen that the voltage change ΔV is determined by the resistance change amount AΔR of the entire MR element.

In general, the electrical conductivity σ (volume) when electrons conducted through a thin film conduct through the volume of the thin film while maintaining its spin is an amount representing the intensity of spin-dependent scattering of electrons conducted through the volume. It can be expressed as follows using the bulk scattering coefficient β and the specific resistance ρ of the thin film. Specifically, the electrical conductivity σ ↑ (volume) of up-spin and the electrical conductivity σ ↓ (volume) of down-spin are as follows.
σ ↑ (volume) = (1 + β) / 2ρ (3)
σ ↓ (volume) = (1-β) / 2ρ (4)
This bulk scattering coefficient β represents the asymmetry between the electrical conductivity σ ↑ (volume) of up-spin and the electrical conductivity σ ↓ (volume) of down-spin,
β = (σ ↑ −σ ↓) / (σ ↑ + σ ↓) (5)
Can be written.

Here, based on the model shown in FIG. 7, the specific resistance change Δρ due to the bulk scattering effect in a general spin valve structure is considered using the above-described bulk scattering coefficient β. FIG. 7 conceptually shows the relationship between the magnetization directions in the magnetization free layer FL and the magnetization pinned layer PL facing each other with the intermediate layer ML interposed therebetween. More specifically, FIG. 7A corresponds to a low resistance state in which the magnetization directions are parallel to each other, and FIG. 7B corresponds to a high resistance state in which the magnetization directions are antiparallel to each other. For simplicity, the electrical resistance of the intermediate layer ML is ignored here. First, the specific resistance ρ (parallel) when the upward spin S ↑ and the downward spin S ↓ pass through the magnetization free layer FL and the magnetization pinned layer PL in the low resistance state of FIG. The specific resistance ρ ↑ (parallel) of the upward spin S ↑ is
ρ ↑ (parallel) = {2ρ / (1 + β)} + {2ρ / (1 + β)}
= 4ρ / (1 + β) (6)
It becomes. The specific resistance ρ ↓ (parallel) of one downward spin S ↓ is
ρ ↓ (parallel) = {2ρ / (1-β)} + {2ρ / (1-β)}
= 4ρ / (1-β) (7)
It becomes. The specific resistance ρ (parallel) considering both the upward spin S ↑ and the downward spin S ↓ in the low resistance state is
ρ (parallel) = (ρ ↑ (parallel) ・ ρ ↓ (parallel)) / (ρ ↑ (parallel) + ρ ↓ (parallel))
From the equations (6) and (7),
ρ (parallel) = 2ρ (8)
It becomes. Similarly, the specific resistance ρ (antiparallel) when the upward spin S ↑ and the downward spin S ↓ pass through the magnetization free layer FL and the magnetization pinned layer PL in the high resistance state of FIG. 7B will be considered. The specific resistance ρ ↑ (antiparallel) of the upward spin S ↑ is
ρ ↑ (antiparallel) = {2ρ / (1 + β)} + {2ρ / (1-β)}
= 4ρ / (1-β ² ) (9)
It becomes. The specific resistance ρ ↓ (antiparallel) of one downward spin S ↓ is
ρ ↓ (antiparallel) = {2ρ / (1-β)} + {2ρ / (1 + β)}
= 4ρ / (1-β ² ) (10)
It becomes. The specific resistance ρ (antiparallel) considering both the upward spin S ↑ and the downward spin S ↓ in the high resistance state is
ρ (antiparallel) = (ρ ↑ (antiparallel) · ρ ↓ (antiparallel)) / (ρ ↑ (antiparallel) + ρ ↓ (antiparallel))
From the equations (9) and (10),
ρ (antiparallel) = 2ρ / (1-β ² ) (11)
It becomes. Therefore, the specific resistance change Δρ (volume) due to the bulk scattering effect in the spin valve structure is expressed by the following equations (8) and (11):
Δρ (volume) = ρ (antiparallel)-ρ (parallel)
= {2ρ / (1-β ² )}-2ρ
= 2ρβ ² / (1-β ² ) (12)
It becomes. Therefore, it can be said that the specific resistance change Δρ increases as the bulk scattering coefficient β increases.

  In the multilayer structure, there is a resistance due to the interface scattering effect at the interface between the layers. In the CPP-GMR element, since the sense current I flows so as to be orthogonal to these interfaces, it is necessary to consider this effect.

In general, the electrical conductivity σ (interface) at an interface can be expressed using an interface scattering coefficient γ. Specifically, the electrical conductivity σ ↑ (interface) of upspin and the electrical conductivity σ ↓ (interface) of downspin are as follows. Here, Rk is the interface resistance per unit area through which the sense current I passes.
σ ↑ (interface) = (1 + γ) / 2Rk · A (13)
σ ↓ (interface) = (1-γ) / 2Rk · A (14)
This interface scattering coefficient γ represents the asymmetry between the electrical conductivity σ ↑ (interface) of the up spin and the electrical conductivity σ ↓ (interface) of the down spin.
γ = (σ ↑ −σ ↓) / (σ ↑ + σ ↓) (15)
Can be written.

Similar to the bulk scattering effect, the interface resistance change ΔRk · A due to the interface scattering effect in a general spin valve structure is considered using the above-described interface scattering coefficient γ by the model shown in FIG. First, the interface resistance Rk · A (parallel) when the upward spin S ↑ and the downward spin S ↓ pass through the magnetization free layer FL and the magnetization pinned layer PL in the low resistance state of FIG. The interface resistance Rk · A ↑ (parallel) of the upward spin S ↑ is
Rk · A ↑ (parallel) = {2Rk · A / (1 + γ)} + {2Rk · A / (1 + γ)}
= 4Rk · A / (1 + γ) (16)
It becomes. The interface resistance Rk · A ↓ (parallel) of one downward spin S ↓ is
Rk · A ↓ (parallel) = {2Rk · A / (1-γ)} + {2Rk · A / (1-γ)}
= 4Rk · A / (1-γ) (17)
It becomes. Interfacial resistance Rk · A (parallel) considering both upward spin S ↑ and downward spin S ↓ in the low resistance state is
Rk · A (parallel) = (Rk · A ↑ (parallel) · Rk · A ↓ (parallel)) / (Rk · A ↑ (parallel) + Rk · A ↓ (parallel))
From the equations (16) and (17),
Rk · A (parallel) = 2Rk · A (18)
It becomes. Similarly, the interface resistance Rk · A (antiparallel) when the upward spin S ↑ and the downward spin S ↓ pass through the magnetization free layer FL and the magnetization pinned layer PL, respectively, in the high resistance state of FIG. 7B is considered. . The interface resistance Rk · A ↑ (antiparallel) of the upward spin S ↑ is
Rk · A ↑ (antiparallel) = {2Rk · A / (1 + γ)} + {2Rk · A / (1-γ)}
= 4Rk · A / (1-γ ² ) (19)
It becomes. The interface resistance Rk · A ↓ (anti-parallel) of one downward spin S ↓ is
Rk · A ↓ (antiparallel) = {2Rk · A / (1-γ)} + {2Rk · A / (1 + γ)}
= 4Rk · A / (1-γ ² ) (20)
It becomes. The interface resistance Rk · A (anti-parallel) considering both the upward spin S ↑ and the downward spin S ↓ in the high resistance state is
Rk · A (antiparallel) = (Rk · A ↑ (antiparallel) · Rk · A ↓ (antiparallel)) / (Rk · A ↑ (antiparallel) + Rk · A ↓ (antiparallel)))
From the equations (19) and (20),
Rk · A (antiparallel) = 2Rk · A / (1-γ ² ) (21)
It becomes. Therefore, the interfacial resistance change ΔRk · A in the spin valve structure is obtained from the equations (18) and (21):
ΔRk · A = Rk · A (antiparallel) -Rk · A (parallel)
= {2Rk · A / (1? Γ ² )}? 2Rk · A
= 2Rk · A · γ ² / (1-γ ² ) (22)
It becomes. Therefore, it can be said that the interface resistance change ΔRk · A increases as the interface scattering coefficient γ increases.

  Here, with respect to the MR element 10, as shown in FIG. 8A, the MR element 10 as a whole exhibits a relatively low resistance state, and as shown in FIG. 8B, the MR element 10 as a whole. Consider the case of a relatively high resistance state. Each arrow in FIGS. 8A and 8B indicates the relative magnetization direction of each layer. However, the antiferromagnetic layer 22 shows a state in which the magnetization direction does not appear macroscopically because the antiparallel magnetizations cancel each other. Specifically, in FIG. 8A, the magnetization direction of the magnetization free layer 25 is the + X direction, parallel to the magnetization direction of the first magnetization pinned film 231, and the magnetization direction of the second magnetization pinned film 233. It is antiparallel. On the other hand, in FIG. 8B, the magnetization direction of the magnetization free layer 25 is the −X direction, antiparallel to the magnetization direction of the first magnetization pinned film 231, and the magnetization direction of the second magnetization pinned film 233. It is parallel. Here, it is considered that the resistance change amount AΔR of the MR element 10 appears as a difference between the low resistance state of FIG. 8A and the high resistance state of FIG. 8B.

The resistance change amount AΔR is divided into two relations: a relation between the magnetization free layer 25 and the first magnetization pinned film 231 and a relation between the magnetization free layer 25 and the second magnetization pinned film 233. First, since the magnetization free layer 25 and the first magnetization pinned film 231 have a magnetization direction parallel to each other in FIG. 8A, the magnetization free layer 25 and the first magnetization pinned film 231 exhibit a relatively low resistance r1, and in FIG. Since it is oriented, it exhibits a relatively high resistance R1 (ie, r1 <R1). One magnetization free layer 25 and the second magnetization pinned film 233 have a relatively high resistance R2 in FIG. 8A because they have antiparallel magnetization directions, and in FIG. 8B, magnetizations parallel to each other. Since it is oriented, it exhibits a relatively low resistance r2 (ie, R2> r2). Therefore, for example, the resistance change amount AΔR when shifting from the low resistance state of FIG. 8A to the high resistance state of FIG. 8B is due to the GMR effect of the magnetization free layer 25 and the first magnetization pinned film 231. Since it is proportional to the sum of the component caused and the component caused by the GMR effect of the magnetization free layer 25 and the second magnetization pinned layer 233,
AΔR∝A (R1-r1) + A (r2-R2) (23)
It can be expressed as. Here, the first term “A (R1-r1)” represents the resistance change amount due to the GMR effect between the magnetization free layer 25 and the first magnetization pinned film 231, and the second term “A (r2-R2)” The resistance change amount due to the GMR effect between the magnetization free layer 25 and the second magnetization pinned film 233 is represented. Here, since R1> r1, the first term “A (R1-r1)” indicates a positive value. On the other hand, the second term “A (r2−R2)” shows a negative value because R2> r2. This is because the magnetization direction relationship between the magnetization free layer 25 and the second magnetization pinned film 233 is always opposite to the magnetization direction relationship between the magnetization free layer 25 and the first magnetization pinned film 231. Is attributed. When the resistance change amount AΔR is expressed by using the specific resistance ρ, the interface resistance Rk, the bulk scattering coefficient β, the interface scattering coefficient γ, and the like based on the equation (23), the following equation 1 is obtained.

In Equation 1, ρ ^* represents ρ / (1-β ² ), and Rk ^* represents Rk / (1-γ ² ). The thicknesses t in the first pinned film 231, the second pinned magnetic film 233, the magnetization free layer 25, the intermediate layer 24, and the nonmagnetic film 232 are represented as t _AP1 , t _AP2 , t _F , t _S , and t _R , respectively. . However, in Equation 1, the specific resistances ρ in the first fixed film 231, the second fixed magnetization film 233, the magnetization free layer 25, the intermediate layer 24, and the nonmagnetic film 232 are respectively _expressed as ρ _AP1 , ρ _AP2 , ρ _F , ρ _S , and ρ _R , which correspond to ρ ^* _AP1 , ρ ^* _AP2 , ρ ^* _F , ρ ^* _S , and ρ ^* _R in Equation ₁ . β _AP1 , β _AP2 , and β _F are bulk scattering coefficients of the first pinned film 231, the second pinned film 233, and the magnetization free layer 25, respectively. The interface resistance between the underlayer 21 and the antiferromagnetic layer 22 and the second pinned film 233 is ARk _{Buf / AP2,} and the interface resistance between the nonmagnetic film 232 and the first pinned film 231 is ARk _{Buf / AP2.} Is ARk _{R / AP1} , the interface resistance between the first magnetization pinned film 231 and the intermediate layer 24 is ARk _{AP1 / S,} and the interface resistance between the intermediate layer 24 and the magnetization free layer 25 is ARk _{S / F} And the interface resistance between the magnetization free layer 25 and the protective layer 26 is ARk _{F / Cap,} and ARk ^* _{Buf / AP2} , ARk ^* _{R / AP1} , ARk ^* _{AP1 / S} , ARk ^* _{S / F} , ARk ^* _{F / Cap} is supported. γ _{AP1 / S} is an interface scattering coefficient between the first magnetization pinned film 231 and the intermediate layer 24, and γ _{S / F} is an interface scattering coefficient between the intermediate layer 24 and the magnetization free layer 25.

In Equation 1, the influence of Formula second term of (23) "A (r2-R2)" is - appearing in the coefficient "-1" in the "β _AP2 ρ ^* _AP2 t _AP2". Normally, the bulk scattering coefficient β and the interface scattering coefficient γ of the material used for the MR element are positive (β, γ> 0) (for example, the bulk scattering coefficient β of the CoFe alloy used for the conventional magnetization pinned film is about 0.65). For this reason, the term “−β _AP2 ρ ^* _AP2 t _AP2 ” with a negative sign is a component that works to reduce the resistance change amount AΔR, so it is desirable to make the absolute value as small as possible. For this reason, in the present embodiment, a ferromagnetic material having a smaller bulk scattering coefficient β (specifically, 0.25 or less, particularly 0.20 or less) is used for the second pinned film 233. I am going to do that. As a result, it is possible to reduce the loss of the resistance change amount AΔR that has occurred in the conventional synthetic CPP-GMR element, so that the resistance change rate ΔR / R is increased and the signal magnetic field is detected with higher sensitivity. Is possible.

  As described above, the MR element 10 according to the present embodiment includes the first magnetization pinned film 231 indicating the magnetization direction fixed in a certain direction, the magnetization direction fixed in the opposite direction, and tantalum, for example. A magnetization pinned layer 23 having a second magnetization pinned film 233 having a bulk scattering coefficient β of 0.25 or less by containing at least one of (Ta), chromium (Cr), and vanadium (V); An MR film 20 including a magnetization free layer 25 provided on the opposite side of the first magnetization pinned film 231 from the second magnetization pinned film 233 and changing the magnetization direction in accordance with an external magnetic field is provided. The film 20 is configured such that a sense current I flows in a direction perpendicular to the laminated surface via the lower and upper electrodes 11 and 14. Thereby, the bulk scattering effect by the second magnetization pinned film 233 acting so as to cancel the resistance change amount (R1-r1) generated between the magnetization free layer 25 and the first pinned film 231 is suppressed. Therefore, it is possible to suppress a decrease in the resistance change amount, improve the resistance change rate ΔR / R, and cope with reading of magnetic information recorded at a higher recording density. In particular, the first and second magnetization pinned films 231 and 233 are exchange-coupled to each other via the nonmagnetic film 232, or the second magnetization pinned film 233 is opposite to the first magnetization pinned film 231. Since the antiferromagnetic layer 22 for fixing the magnetization direction of the second magnetization pinned film 233 is further provided, the stability of the magnetization direction in the magnetization pinned layer 23 is improved, and a more stable resistance change amount AΔR is obtained. And can cope with higher recording density.

  Next, a method for manufacturing the thin film magnetic head 1 will be described with reference to FIGS. Here, the part which mainly forms MR element 10 is demonstrated in detail.

  In the method of manufacturing the thin film magnetic head according to the present embodiment, the step of forming the lower electrode 11 on the substrate 8 and the antiferromagnetic layer 22 and the magnetization fixed layer on the lower electrode 11 from the lower electrode 11 side are provided. A step of forming a multilayer film 20Z including a structure in which an intermediate layer 24, an intermediate layer 24, and a magnetization free layer 25 are disposed in order, and a region corresponding to a portion defining the element width is protected on the multilayer film 20Z. The step of selectively forming the photoresist pattern 61, the step of forming the MR element 10 by selectively etching the multilayer film 20Z using the photoresist pattern 61 as a mask, After selectively forming the magnetic film, the step of forming the pair of magnetic domain control films 12 via the insulating film 15 by removing the photoresist pattern 61 and the pair of magnetic domain control films 1 Forming an insulating film 13 on the, after removing the photoresist pattern 61, it is intended to include forming an upper electrode 14 over the entire surface. Hereinafter, each step will be described in more detail.

  First, as shown in FIG. 9, the multilayer film 20 </ b> Z is formed over the entire surface of the lower electrode 11 formed on one side surface of the substrate 8. Specifically, the underlayer 21, the antiferromagnetic layer 22, the magnetization pinned layer 23, the intermediate layer 24, the magnetization free layer 25, and the protective layer 26 are sequentially stacked using sputtering or the like. This multilayer film 20Z will become the MR film 20 later. 9 to 13, illustration of the internal structure of the MR film 20 and the multilayer film 20Z in the process of forming the MR film 20 is omitted, but any of the internal structures corresponding to the MR film 20 shown in FIG. Have.

  Subsequently, as shown in FIG. 10, a photoresist pattern 61 is selectively formed on the multilayer film 20Z so as to have a width W corresponding to a portion defining the element width. In this case, the end portion of the photoresist pattern 61 may be partially removed using a predetermined solvent to form an undercut.

  Thereafter, the multilayer film 20Z is selectively removed using dry etching such as ion milling or RIE using the photoresist pattern 61 as a mask. In this case, dry etching is performed until the lower electrode 11 is reached. As a result, as shown in FIG. 11, the MR film 20 having the width Tw is formed. This width Tw is an average element width of the MR film 20. After the MR film 20 is formed, as shown in FIG. 12, a pair of insulating films 15 and a pair of magnetic domain control films 12 are formed so as to be adjacent to both sides of the MR film 20 in the X direction. Specifically, for example, the insulating film 15, the base layer 121, and the magnetic domain control layer 122 are sequentially formed over the entire surface by sputtering or the like. Further, an insulating film 13 is formed on the magnetic domain control film 12 by sputtering. Next, the photoresist pattern 61 is lifted off, so that the MR film 20, a pair of insulating films 15 that are opposed to each other, and a pair of magnetic domain control films 12 including a base layer 121 and a magnetic domain control layer 122 appear.

  After removing the photoresist pattern 61, the upper electrode 14 is formed over the entire surface as shown in FIG. Thereby, the MR element 10 is completed once. Thereafter, as shown in FIGS. 3 and 4, the insulating layer 16 is formed over the entire surface, thereby completing the reproducing head portion 1A. Subsequently, the lower magnetic pole 41 and the recording gap layer 42 are sequentially formed on the reproducing head portion 1A, and the coil 44 is selectively formed on the recording gap layer 42. Thereafter, a part of the recording gap layer 42 is etched to form an opening 42A. Next, an insulating layer 45 is formed so as to cover the coil 44, and a pole tip 43 and a connecting portion 46 are sequentially formed. Finally, the upper magnetic pole 47 is formed so as to cover the whole, thereby completing the recording head portion 1B. Thereafter, the thin film magnetic head 1 is completed through a predetermined process such as machining the slider 2A to form the recording medium facing surface 2F.

  Next, specific examples of the present invention will be described.

The first and second examples (Examples 1 and 2) of the present invention described below include the MR element 10 having the cross-sectional structure shown in FIG. 5 based on the manufacturing method described in the above embodiment. Samples of the thin film magnetic head 1 were formed, and the characteristics of these samples were investigated. Details will be described below with reference to Tables 1 to 5 and FIG. The samples of Examples 1 and 2 have the following common configuration. Here, the formation area A of the MR element 10 (MR film 20) is 0.01 μm ² (0.1 μm × 0.1 μm) in all cases.

<Common configuration>
Ta1 / NiFeCr5 / IrMn7 / "AP2" /Ru0.8/[CoFe1/Cu0.2]2/CoFe1/Cu3.2/CoFe1.5/Cu0.3/CoFe1.5/Cap

  In the above common configuration, the numerical value given to each material name indicates the thickness (unit: nanometer: nm) of each layer. However, [CoFe1 / Cu0.2] 2 indicates a structure in which a CoFe layer having a thickness of 1 nm and a copper layer having a thickness of 0.2 nm are alternately and repeatedly stacked twice. In the above-described common configuration, a laminated structure (Ta1 / NiFeCr5) of a 1 nm thick Ta layer and a 5 nm thick NiFeCr layer corresponds to the underlayer 21, and a 7 nm thick IrMn layer (IrMn7) corresponds to the antiferromagnetic layer 22. To do. Further, the second magnetization pinned film 233 (“AP2”), the nonmagnetic film 232 made of ruthenium (Ru0.8) having a thickness of 0.8 nm, [CoFe1 / Cu0.2] 2 and 1 nm having the above-described configuration The first pinned film 23A made of thick CoFe constitutes the pinned layer 23. Further, a copper layer (Cu3.2) having a thickness of 3.2 nm corresponds to the intermediate layer 24, and two ferromagnetic films 251 and 253 made of CoFe (CoFe1.5) having a thickness of 1.5 nm and copper having a thickness of 0.3 nm are used. The nonmagnetic film 252 made of (Cu0.3) constitutes the magnetization free layer 25.

The samples of Examples 1 and 2 differ from each other only in the configuration of the second pinned film 233 indicated by “AP2” in the above-described common configuration. Here, the second magnetization pinned film 233 having a different composition was formed using an alloy material obtained by adding an additive substance X containing any one of tantalum, chromium, and vanadium to CoFe. This is collectively expressed as CoFeX (X = Ta, Cr, V). The total thickness of CoFeX was set to 3 nm. In the above-mentioned common configuration, the composition ratio in CoFe is all Co: Fe = 9: 1. For each example sample thus created, the resistance RA (Ω · μm ² ), the resistance change amount AΔR (mΩ · μm ² ), the resistance change rate MR (%) and the second magnetization pinned film 233 of the entire element. Each value of the bulk scattering coefficient β was determined. The resistance RA and the resistance change amount AΔR were measured by a general four-terminal method. A method for calculating the bulk scattering coefficient β will be described later.

<Example 1>
In this example, the case where X = Ta, that is, the case where the second magnetization fixed film 233 (“AP2”) is configured using a cobalt iron tantalum alloy (CoFeTa) is investigated. Here, the content of tantalum was set to four types of 0.8 at%, 1.0 at%, 5.0 at%, and 10.0 at% with respect to the entire second magnetization pinned film 233. The results are shown in Table 1.

<Example 2>
In this embodiment, when X = Cr or X = V, that is, the second magnetization pinned film 233 (“AP2”) is configured using a cobalt iron chromium alloy (CoFeCr) or a cobalt iron vanadium alloy (CoFeV). This is a survey of cases where Here, each content of chromium and vanadium was set to four types of 11 at%, 13 at%, 16 at%, and 19 at% with respect to the entire second magnetization pinned film 233. The results are shown in Table 2.

<Comparative Example 1>
Here, the second magnetization pinned film (“AP2”) which is composed of only CoFe and does not contain other materials such as tantalum, chromium, vanadium, and the like is referred to as Comparative Example 1 for each of the above examples. The same items as in the example were investigated. The comparative example 1 is exactly the same as the common configuration of the examples except for the second magnetization fixed film. The results are shown in Table 3.

  The bulk scattering coefficient β is a specific value determined by the material composition. The values shown in the column of “β” in Tables 1 to 3 are obtained by performing the following auxiliary experiment.

  In obtaining the bulk scattering coefficient β in the second magnetization pinned film 233, for the sake of simplicity, a sample of a spin valve structure (conventional type) having a single magnetization pinned layer instead of a synthetic type is used for each composition. It produced about the composition ratio of a kind, measured resistance change amount A (DELTA) R, and also was calculated from those proportional relationship (Example 3). Also in this case, a comparative example (referred to as Comparative Example 2) in which the magnetization pinned layer was made of only CoFe was produced.

<Example 3>
The detailed configuration of each sample for which the auxiliary experiment was conducted is as follows:
Ta1 / NiFeCr5 / IrMn7 / CoFeX5 / Cu3 / CoFe2 / Cap
It is. In addition, the number attached | subjected to the material name of each layer represents the thickness (nm) of each layer. Specifically, “Ta / NiFeCr” is the underlayer 21, “IrMn” is the antiferromagnetic layer 22, “CoFeX” is the magnetization pinned layer 23, “Cu” is the intermediate layer 24, and “CoFe” is the magnetization free layer 25. , “Cap” corresponds to the protective layer 25, respectively. Here, X is an additive substance representing any one of Ta, Cr, and V. Each content was four types with respect to the whole magnetization fixed film (CoFeX5). Table 4 shows measured values of the resistance change AΔR in that case.

<Comparative example 2>
Moreover, the structure of the sample as the comparative example 2 with respect to Example 3 is as follows.
Ta1 / NiFeCr5 / IrMn7 / CoFe5 / Cu3 / CoFe2 / Cap
It is. “CoFe5” corresponds to the magnetization pinned layer 23.

  When the resistance change amount in the sample of Comparative Example 2 is AΔR (ratio 2) and the resistance change amount in the sample of Example 3 is AΔR (actual 3), these ratios are expressed as in the following formula (24). be able to.

AΔR (ratio 2): AΔR (actual 3)
= {Β (CoFe) ρ ^* (CoFe) t (CoFe) + γ (CoFe / Cu) ARk ^* (CoFe / Cu)}
: {Β (X) ρ ^* (X) t (X) + γ (CoFe / Cu) ARk ^* (CoFe / Cu)} (24)

The following numerical values have already been obtained from literature and the like.
AΔR (ratio 2) = 0.94 (mΩμm ² ),
β (CoFe) = 0.65
ρ ^* (CoFe) t (CoFe) = 0.578,
γ (CoFe / Cu) = 0.75
ARk ^* (CoFe / Cu) = 0.52 (mΩμm ² )
Substituting these numerical values into the equation (24), the equation can be rewritten as the following equation (25).

AΔR (actual 3)
= 0.94 × {β (X) ρ ^* (X) t (X) + 0.75 × 0.52}
/(0.65×0.578+0.75×0.52)
≒ 1.23 × β (X) ρ ^* (X) t (X) +0.48 (25)
From this formula (25) and the results of Table 4, the bulk scattering coefficient β in each material composition shown in Tables 1 to 3 could be obtained.

  As described above, when Examples 1 and 2 shown in Table 1 and Table 2 are compared on the basis of Comparative Example 1 shown in Table 3, when the content of additive substance X increases, resistance change amount AΔR and resistance are increased. It was found that each value of the rate of change MR tends to improve. Specifically, in the case of Example 1, when the tantalum content is 1.0 at% or more, each value of the resistance change amount AΔR and the resistance change rate MR ratio is improved as compared with Comparative Example 1. Similarly, in the case of Example 2, it was found that when the chromium and vanadium contents were 13 at% or more, the resistance change AΔR was improved as compared with the comparative example. That is, in any of Examples 1 and 2, by setting the bulk scattering coefficient β in the second magnetization pinned film 233 to 0.25 or less (particularly preferably 0.20 or less), a larger resistance change amount AΔR can be obtained. It was confirmed that it was obtained.

By the way, in order to function as a spin valve MR element, the first and second magnetization fixed films 231 and 233 need to be antiferromagnetically exchange-coupled via the nonmagnetic film 232. However, as the content of the additive substance X in the second pinned film 233 increases, spin scattering becomes active and the resistance change amount AΔR is improved, while the magnetization M (AP2) is decreased. It is desirable that the magnetization M (AP2) in the second magnetization pinned film 233 be approximately the same as the magnetization M (AP1) of the first magnetization pinned film 231 that is the partner of exchange coupling. Actually, it is only necessary that the sum of magnetizations considering each volume is equal to each other.
M (AP1) × t (AP1) = M (AP2) × t (AP2)
If it becomes. Here, t (AP1) represents the film thickness of the first magnetization pinned film 231 and t (AP2) represents the film thickness of the second magnetization pinned film 233. Therefore, the film thickness t (AP2) may be increased by the amount that the magnetization M (AP2) has decreased due to the increase in the content of the additive substance X. However, when the film thickness t (AP2) is increased, the interface roughness increases and antiferromagnetic exchange coupling becomes difficult, so the limit is about 1.5 times the film thickness t (AP1). For this reason, the upper limit of the magnetization M (AP2) is considered to be about 930 × 10 ³ A / m (= 930 emu / cm ³ ). Here, the relationship between the content of the additive substance X and the magnetization M (AP2) is shown in FIGS. 14A and 14B for Examples 1 and 2, respectively.

14A and 14B, the horizontal axis represents the content [at%] of the additive substance X, and the vertical axis represents the magnetization M (AP2) [× 10 ³ A / m]. 14A and 14B, the content of additive substance X corresponding to the upper limit 930 × 10 ³ A / m of magnetization M (AP2) is 11.8 at% in the case of tantalum, chromium Is 26.5 at% for vanadium, and 29.4 at% for vanadium. Therefore, from the results shown in Tables 1 and 2 and FIGS. 14A and 14B, the preferable range of the content of each additive substance X is 1.0 at% to 11.8 at% for tantalum, and for chromium, It was found to be 13 at% to 26.5 at%, and for vanadium, 13 at% to 29.4 at%.

  Although the present invention has been described with reference to the embodiments and some examples, the present invention is not limited to these embodiments and examples and can be variously modified. For example, in the present embodiment and examples, the MR element having the bottom type synthetic spin valve structure has been described as an example, but the present invention is not limited to this, and the top type may be used. In the present embodiment and example, a single spin valve MR element having one synthetic magnetization pinned layer has been described as an example. However, the present invention is not limited to this, and the synthetic magnetization pinned layer is not limited to this. It is also possible to provide a dual spin valve type MR element having two. Also in this case, a high resistance change rate can be obtained by forming the magnetization pinned film far from the magnetization free layer out of the two magnetization pinned films in each magnetization pinned layer with a material having a bulk scattering coefficient of 0.25 or less. Therefore, it becomes possible to cope with a higher recording density.

It is a perspective view showing the structure of the actuator arm provided with the thin film magnetic head which concerns on one embodiment of this invention. It is a perspective view showing the structure of the slider in the actuator arm shown in FIG. 1 is an exploded perspective view showing a configuration of a thin film magnetic head according to an embodiment of the invention. It is sectional drawing showing the structure of the arrow direction along the IV-IV line of the thin film magnetic head shown in FIG. FIG. 5 is a cross-sectional view illustrating a configuration of a main part when viewed from the direction of arrow V of the thin film magnetic head illustrated in FIG. 4. FIG. 6 is an explanatory diagram for explaining a change in voltage when a sense current is passed through the MR element shown in FIG. 5 in a direction perpendicular to the laminated surface. It is a conceptual diagram for demonstrating the specific resistance change by the bulk scattering effect in a general spin valve structure. FIG. 6 is an explanatory diagram for explaining the relationship between resistance and magnetization direction when a sense current is passed in a direction orthogonal to the laminated surface in the MR element shown in FIG. 5. FIG. 6 is an essential part cross-sectional view showing one step in the method of manufacturing the thin film magnetic head shown in FIG. 5. FIG. 10 is an essential part cross-sectional view illustrating a process following FIG. 9. It is principal part sectional drawing showing the 1 process following FIG. FIG. 12 is an essential part cross-sectional view illustrating a process following FIG. 11. It is principal part sectional drawing showing the 1 process following FIG. It is a characteristic view showing the relationship between the additive substance and the magnetization in the second magnetization fixed film of the first and second embodiments (Examples 1 and 2) of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Thin film magnetic head, 2 ... Head gimbal assembly (HGA), 2A ... Slider, 2B ... Suspension, 3 ... Arm, 4 ... Drive part, 5 ... Fixed shaft, 6 ... Bearing, 7 ... Spindle motor, 8 ... Base | substrate, DESCRIPTION OF SYMBOLS 9 ... Recording medium opposing surface, 10 ... Magnetoresistive effect (MR) element, 11 ... Lower electrode, 12 ... Magnetic domain control film, 13, 15 ... Insulating film, 14 ... Upper electrode, 16 ... Insulating layer, 20 ... MR film, DESCRIPTION OF SYMBOLS 21 ... Underlayer, 22 ... Antiferromagnetic layer, 23 ... Magnetization fixed layer, 231 ... 1st magnetization fixed film, 232 ... Nonmagnetic film, 233 ... 2nd magnetization fixed film, 24 ... Intermediate layer, 25 ... Magnetization Free layer, 26 ... protective layer, 41 ... lower magnetic pole, 42 ... recording gap layer, 43 ... pole tip, 44 ... coil, 45 ... insulating layer, 46 ... connecting part, 47 ... upper magnetic pole, 100 ... housing, 200 ... Magnetic recording medium, 300 ... Arm assembly (HAA).

Claims (16)

A first magnetization pinned film showing a magnetization direction fixed in a fixed direction, a magnetization direction fixed in a direction opposite to the magnetization direction of the first magnetization fixed film, and a bulk scattering coefficient of 0.25 or less A magnetization pinned layer having a second magnetization pinned film shown;
A magnetization free layer provided on a side opposite to the second magnetization pinned film of the first magnetization pinned film and showing a magnetization direction that changes according to an external magnetic field;
A magnetoresistive effect element comprising: a current path through which a sense current flows in a direction perpendicular to the laminated surface with respect to the magnetization fixed layer and the magnetization free layer.   The magnetoresistive effect element according to claim 1, wherein the second magnetization pinned film exhibits a bulk scattering coefficient of 0.20 or less. The second magnetization pinned film includes at least one of tantalum (Ta), chromium (Cr), and vanadium (V).
The magnetoresistive effect element according to claim 1, wherein the magnetoresistive effect element is provided. 4. The magnetoresistive element according to claim 3 , wherein a content of the tantalum (Ta) is 1 atomic percent or more and 11.8 atomic percent or less of the second magnetization pinned film. 4. The magnetoresistive element according to claim 3 , wherein a content of the chromium (Cr) is not less than 13 atomic percent and not more than 26.5 atomic percent of the second magnetization pinned film. 4. The magnetoresistive element according to claim 3 , wherein a content of the vanadium (V) is not less than 13 atomic percent and not more than 29.4 atomic percent of the second magnetization pinned film. The second magnetization pinned film further includes:
The magnetoresistance effect according to any one of claims 3 to 6 , comprising at least one of iron (Fe), cobalt (Co), nickel (Ni), and manganese (Mn). element. The magnetoresistive effect element according to claim 7 , wherein a composition ratio of the cobalt and the iron is 9: 1. 9. The magnetoresistive element according to claim 1, wherein the first and second magnetization fixed films are exchange-coupled to each other through a nonmagnetic film. The anti-ferromagnetic layer for fixing the magnetization direction of the second magnetization pinned film is further provided on the opposite side of the second magnetization pinned film to the first magnetization pinned film. The magnetoresistive effect element of any one of Claim 1-9. The magnetoresistive effect element according to any one of claims 1 to 10 , further comprising an intermediate layer between the magnetization pinned layer and the magnetization free layer. The current path claims 1 to 11, characterized in that in the direction perpendicular to the stacking surface the a first and second electrode layers which are opposed so as to sandwich the magnetization pinned layer and the magnetization free layer The magnetoresistive effect element of any one of these. A thin film magnetic head comprising the magnetoresistive element according to any one of claims 1 to 12 . A magnetic head slider having a thin film magnetic head having the magnetoresistive effect element according to any one of claims 1 to 12 provided on one side surface;
A head gimbal assembly, wherein the magnetic head slider has a suspension attached to one end. A magnetic head slider having a thin film magnetic head having the magnetoresistive effect element according to any one of claims 1 to 12 provided on one side surface;
A suspension in which the magnetic head slider is attached to one end;
An arm that supports the other end of the suspension. A magnetic disk drive comprising a magnetic recording medium and a head arm assembly,
The head arm assembly includes:
A magnetic head slider having a thin film magnetic head having the magnetoresistive effect element according to any one of claims 1 to 12 provided on one side surface;
A suspension in which the magnetic head slider is attached to one end;
An arm that supports the other end of the suspension;
A magnetic disk drive comprising:

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