JP2008192269A - Magnetic read head and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a bias magnetic field-impressing system suitable to a magnetic read head having magnetoresistive sensor multiple layers where a sense current flows through them in the stacking direction. <P>SOLUTION: In an embodiment of this invention, a reproducing head 11 has an in-stack ferromagnetic film 217 forming a bias magnetic field to be applied to a free layer 215. There is an in-stack bias interlayer 216 between the in-stack ferromagnetic film 217 and the free layers 215 to control the exchange coupling force between them. The ferromagnetic film 118 controls the magnetizing direction of the stacked in-stack ferromagnetic films 217. The magnetizing direction of the ferromagnetic film 118 is fixed by a hard biasing film 115. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a magnetic read head and a manufacturing method thereof, and more particularly to a magnetic read head in which a sense current flows in a stacking direction of a magnetoresistive sensor multilayer film and a manufacturing method thereof.

  A hard disk drive (HDD) includes a magnetic recording medium and a magnetic head, and data on the magnetic recording medium is read and written by the magnetic head. A magnetic head in the HDD includes a recording head that records information as a magnetization signal on a magnetic recording medium (magnetic disk), and a reproducing head that reads a signal recorded as a magnetization signal on the magnetic recording medium. The reproducing head is composed of a magnetoresistive layered body composed of a plurality of magnetic thin films and a nonmagnetic thin film, and reads a signal using the magnetoresistive effect, so that it is called a magnetoresistive head.

  There are several types of laminated structures of magnetoresistive effect heads, and they are classified into AMR heads, GMR heads, CPP-GMR heads, TMR heads and the like based on the principles of magnetoresistance used. AMR (magnetoresistance effect), GMR (giant magnetoresistance effect), CPP-GMR effect (Current Perpendicular Plane GMR effect), and TMR (tunnel magnetoresistance effect) are used to enter the read head from the magnetic recording medium, respectively. The input magnetic field is extracted as a voltage change.

Currently, with the progress of higher sensitivity, a more sensitive reproduction method is required. In the range of 70 to 150 (Gb / in ² ), TMR having a very high MR ratio is advantageous in terms of improving sensitivity. Then, it is considered that CPP-GMR or the like becomes mainstream for ultra-high recording density exceeding 150 (Gb / in ² ). About TMR, it is disclosed by patent document 1, for example. CPP-GMR is disclosed in, for example, Patent Document 2. TMR and CPP-GMR are different from CIP-GMR (Current In Plane GMR) in which a sense current flows in parallel to the film surface of the magnetoresistive stack, and are in a direction perpendicular to the film surface, that is, in the stacking direction of the film surface. This is a method of flowing a sense current. In this specification, such a method is called a CPP method. Such a reproducing head is called a CPP type reproducing head.

  FIG. 18 is a cross-sectional view schematically showing a configuration of a conventional CPP type reproducing head 71. The left-right direction in FIG. 18 is the track width direction. The magnetoresistive sensor 712 is between the lower shield 711 and the upper shield 713. The lower shield 711 and the upper shield 713 function as a magnetic shield and also serve as a lower electrode and an upper electrode that supply a sense current to the magnetoresistive sensor 712. A magnetic isolation film 714 exists under the upper shield 713. The sensor gap between the lower shield 711 and the upper shield 713 is indicated by Gs. Further, a step in the track width direction of the upper shield 713 is indicated by Usbs.

  The magnetoresistive sensor 712 includes a sensor base layer 271, an antiferromagnetic film 272, a fixed layer 273, a nonmagnetic intermediate layer 274, a free layer 275, and a sensor cap film 276, which are sequentially stacked from the lower layer side. . The fixed layer 273 in FIG. 18 is a laminated fixed layer. An exchange interaction with the antiferromagnetic film 272 acts on the fixed layer 273 and its magnetization direction is fixed. When the reproducing head 71 is a TMR head, the nonmagnetic intermediate layer 274 is formed of an insulator such as magnesium oxide (MgO). When the CPP-GMR is used, the nonmagnetic intermediate layer 274 is made of a nonmagnetic conductor such as Cu. Formed using. The track width of the free layer 275 is indicated by Twf.

  When the relative magnetization direction of the free layer 275 with respect to the magnetization direction of the fixed layer 273 changes due to the magnetic field from the magnetic disk, the resistance value (current value) of the magnetoresistive sensor 712 changes. Thus, the reproducing head 71 can detect an external magnetic field. Hard bias films 715 exist on the left and right sides of the magnetoresistive sensor 712. The bias magnetic field from the hard bias film 715 works to make the free layer 275 a single magnetic domain. The hard bias film 715 is formed on the hard bias base film 716. A junction insulating film 717 is formed as a lower layer of the hard bias base film 716. The junction insulating film 717 exists between the hard bias base film 716, the lower shield film 711, and the magnetoresistive sensor 712, and prevents the sense current from flowing outside the magnetoresistive sensor 712.

  FIG. 19A is a cross-sectional view of the CPP reproducing head 71 in FIG. 18, and the left side is the ABS (Air Bearing Surface) surface side facing the magnetic disk. On the rear side (right side in the drawing) of the magnetoresistive sensor 712, there is a first rear end insulating film 717 and a second rear end insulating film 718 below it. These insulating films also prevent the sense current from flowing outside the magnetoresistive sensor 712. The backward step difference of the upper shield 713 is indicated by Usbb.

  FIG. 19B shows the positional relationship between the free layer 275 and the hard bias film 715 in the CPP type reproducing head 71. The CPP reproducing head 71 has hard bias films 715 on the left and right sides of the free layer 275 in the track width direction. It does not exist behind the free layer 275. As a method of applying a bias magnetic field to the free layer 275, an in-stack type in which a bias layer is laminated on the magnetoresistive sensor 712 instead of forming a hard bias film on the side of the magnetoresistive sensor 712 as described above is known. It has been. An example of such an in-stack bias layer is disclosed in Patent Document 3, for example.

  20A and 20B are schematic views showing the magnetization directions of the components of the CPP reproducing head 71. FIG. As shown in FIG. 20A, the initial magnetic field of the free layer 275 is determined by the bias magnetic field generated by the hard bias film 715. The initial state of the free layer 275 has magnetization in the same direction as the hard bias film 715. As shown in FIGS. 20A and 20B, the fixed layer 273 has two ferromagnetic layers that are antiferromagnetically coupled. These magnetization directions are perpendicular to the initial magnetization direction of the free layer. In order to antiferromagnetically couple the two ferromagnetic layers, Ru metal is typically used as the intermediate layer.

  Next, a manufacturing process of the CPP reproducing head 71 will be described with reference to FIG. First, a multilayer film constituting the magnetoresistive sensor 712 is deposited by sputtering (S301). Thereafter, the rear end of the magnetoresistive sensor 712 is formed. Specifically, the resist depth (dimension in the direction opposite to the magnetic disk from the ABS surface) is determined by resist application and patterning (S302). The rear end portion of the magnetoresistive sensor 712 is formed by ion milling (S303). Further, insulating films 717 and 718 at the rear end of the magnetoresistive sensor 712 are formed (S304), and then the resist is lifted off (S305).

Subsequently, the shape of the magnetoresistive sensor 712 in the track width direction and other structures are formed. First, a resist track width is formed by resist application and patterning (S306), and a track width of the multilayer magnetoresistive sensor 712 is formed by etching using ion milling (S307). Thereafter, a junction insulating film 717 is formed (S308). Further, a hard bias base film 716 and a hard bias film 715 are formed (S309), and then the resist is lifted off (S310). Thereafter, an upper shield film 713 is formed. Specifically, an upper shield isolation nonmagnetic film 714 is formed (S311). Thereafter, an upper shield film 713 is formed on the upper shield base film.
Japanese Patent Laid-Open No. 3-154217 Japanese National Patent Publication No. 11-509956 JP 2006-179666 A

  As described above, when the hard bias film 715 is formed on both the left and right sides in the track width direction of the magnetoresistive sensor 712, the hard bias film 715 has an appropriate thickness (see FIG. 18 in the vertical direction). One of the problems caused by the thick hard bias film 715 is that the step Usbs of the upper shield 713 increases.

  If a large step Usbs is formed on the upper shield 713 in the vicinity of the side end of the magnetoresistive sensor 712, the upper shield 713 is not flattened on the magnetoresistive sensor 712, or the flattened width is reduced. As described above, if the upper shield 713 is not sufficiently flattened with respect to the free layer track width Twf, the effect of the upper shield 113 is reduced at the end of the magnetoresistive sensor 112, and there is a problem that the reading blur width is increased.

  The in-stack type bias magnetic field application method is preferable to the bias magnetic field application method using the hard bias films 715 on both the left and right sides in the track width direction in terms of flattening the upper shield 713. However, the shape of the in-stack bias film is substantially the same as the shape of the free layer, KuV / KT becomes small, and the thermal stability of the magnetized state tends to be lowered. In particular, there is a problem that the signal thermal stability in a narrow track width is not excellent.

  Alternatively, in the in-stack bias system, it is necessary to form a bias film for generating a bias magnetic field on the magnetoresistive sensor, but it is technically difficult to form a hard magnetic film directly here. Also, stacking many layers on the magnetoresistive sensor to generate a bias magnetic field increases the sensor gap Gs and degrades the read characteristics.

  One aspect of the present invention includes a magnetoresistive film having a stacked free layer, a fixed layer, and a nonmagnetic layer between the free layer and the fixed layer, and is perpendicular to the film surface of the magnetoresistive film. A magnetic read head in which current flows in the direction. This magnetic read head is laminated on the magnetoresistive effect film, and is disposed on the side of the ferromagnetic film, an in-stack ferromagnetic film that controls the magnetization state of the free layer by an exchange coupling force, and a bias magnetic field And a ferromagnetic material that is laminated in magnetic contact with each of the in-stack ferromagnetic film and the side ferromagnetic film and transmits magnetization to the in-stack ferromagnetic film. Has a membrane. By controlling the magnetization of the in-stack ferromagnetic film with the side ferromagnetic film and the ferromagnetic film between them, a stable and appropriate bias magnetic field can be applied to the free layer.

  The pinned layer, the nonmagnetic layer, and the free layer are sequentially laminated from the substrate side, the in-stack ferromagnetic film is disposed on the free layer, and the ferromagnetic film is The lower surface of the side ferromagnetic film is preferably disposed above the upper surface of the free layer. More preferably, the lower surface of the side ferromagnetic film substantially coincides with the upper surface of the in-stack ferromagnetic film. Thereby, it is possible to prevent the magnetic field of the side ferromagnetic film from being directly applied to the free layer.

  The pinned layer, the nonmagnetic layer, and the free layer are sequentially laminated from the base side in the order of the track width direction on the film surface or the direction perpendicular to the track width direction. It is preferable that it is larger than the dimension. As a result, the characteristics of the magnetoresistive film can be improved.

  It is preferable that a magnetic shield film having a soft magnetic layer is disposed in the vicinity of both end portions of the free layer, and the side ferromagnetic film is disposed on the magnetic shield film. Thereby, external noise can be suppressed. Furthermore, it is preferable that the magnetic shield film has a soft magnetic film having a laminated structure of at least two layers having an interlayer coupling structure. Thus, the coupling energy can be adjusted so as not to affect the free layer when the shield layer is operated.

  In a preferred aspect, the side ferromagnetic film is formed on both sides and the back side in the track width direction of the magnetoresistive film. As a result, the thickness of the side ferromagnetic film can be reduced. Alternatively, the side ferromagnetic film is preferably formed only on the back side of the magnetoresistive film. By not forming the ferromagnetic films on both sides, the upper shield step can be reduced. In a preferred aspect, the side ferromagnetic film includes a Co alloy film, a Cr alloy base film, and an amorphous alloy seed film for controlling the crystal orientation of the base film. Thereby, a side ferromagnetic film having appropriate characteristics can be formed.

  A control film for controlling an exchange coupling magnetic field is provided between the in-stack ferromagnetic film and the free layer, and the fixed layer controls two soft magnetic layers and an exchange coupling magnetic field between them. The exchange coupling magnetic field between the in-stack ferromagnetic film and the free layer is preferably smaller than the exchange coupling magnetic field in the fixed layer. This makes it possible to apply a bias magnetic field having an appropriate strength to the free layer.

  Another aspect of the present invention is a method of manufacturing a magnetic read head in which current flows in a direction perpendicular to the film surface of the magnetoresistive film. This method forms a magnetoresistive film having a laminated free layer, a fixed layer, and a nonmagnetic layer between the free layer and the fixed layer. An in-stack ferromagnetic film that is laminated on the magnetoresistive film and controls the magnetization state of the free layer by an exchange coupling force is formed. A side ferromagnetic film that is disposed on the side of the ferromagnetic film and generates a bias magnetic field is formed. Then, the in-stack ferromagnetic film and the side ferromagnetic film are laminated in magnetic contact with each other to form a ferromagnetic film that controls the magnetization of the in-stack ferromagnetic film. By controlling the magnetization of the in-stack ferromagnetic film with the side ferromagnetic film and the ferromagnetic film between them, a stable and appropriate bias magnetic field can be applied to the free layer.

  The magnetoresistive film is formed in the order of the fixed layer, the nonmagnetic layer, and the free layer. The in-stack ferromagnetic film is disposed on the free layer. A ferromagnetic film that controls the magnetization of the in-stack ferromagnetic film is disposed on the in-stack ferromagnetic film. The lower surface of the side ferromagnetic film is preferably disposed above the upper surface of the free layer. More preferably, the side ferromagnetic film is formed such that the lower surface of the side ferromagnetic film substantially coincides with the upper surface of the in-stack ferromagnetic film.

  The pinned layer, the nonmagnetic layer, and the free layer are sequentially laminated from the substrate side. Preferably, the fixed layer and the free layer are formed so that a dimension of the fixed layer is larger than a dimension of the free layer in a track width direction or a direction perpendicular to the track width direction in the film surface.

  Preferably, a magnetic shield film having a soft magnetic layer is further formed in the vicinity of both end portions of the free layer, and the side ferromagnetic film is formed on the magnetic shield film. Furthermore, it is preferable that the magnetic shield film has a soft magnetic film having a laminated structure of at least two layers having an interlayer coupling structure.

  According to the present invention, a bias magnetic field application method suitable for a magnetic read head having a magnetoresistive sensor multilayer film in which a sense current flows in the stacking direction is realized.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to the same element, and duplication description is abbreviate | omitted as needed for clarification of description. In the embodiment described below, the present invention is applied to a reproducing head of a hard disk drive (HDD) which is an example of a magnetic read head. The reproducing head of this embodiment is a CPP (Current Perpendicular Plane) type head in which a sense current flows in the stacking direction of the magnetoresistive sensor multilayer film (direction perpendicular to the film surface). In particular, this embodiment is characterized by a method of applying a bias to the free layer of the magnetoresistive sensor.

  Before describing the features of this embodiment, the overall configuration of the magnetic head will be described first. FIG. 1 is a cross-sectional view schematically showing the structure of the magnetic head 1. The magnetic head 1 reads and writes magnetic data from and to the magnetic disk 3. In FIG. 1, the magnetic disk 2 rotates in the right direction, and the traveling direction of the magnetic head 11 is the left direction in FIG. The magnetic head 1 has a reproducing head 11 and a recording head 12 from the running direction side (leading side). The reproducing head 11 is a magnetic read head, and the recording head 12 is a write head. The magnetic head 1 is formed on the trailing side of the slider 2 (the side opposite to the leading side). The magnetic head 1 and the slider 2 constitute a head slider. The reproducing head 11 has a lower shield 111, a magnetoresistive sensor 112, and an upper shield 113 from the leading side. The recording head 12 has a thin film coil 121 and a recording magnetic pole 122. The thin film coil 121 is surrounded by an insulator 123.

  The recording head 12 is an inductive element that generates a magnetic field between the recording magnetic poles 122 by a current flowing through the thin film coil 121 and records magnetic data on the magnetic disk 11. The reproducing head 11 is a magnetoresistive element and includes a magnetoresistive sensor 112 having magnetic anisotropy. The reproducing head 11 receives magnetic data recorded on the magnetic disk 2 according to the resistance value that changes according to the magnetic field from the magnetic disk 2. read out. The reproducing head of this embodiment is a CPP type reproducing head, and the lower shield 111 and the upper shield 113 are used as electrodes for supplying a detection current to the magnetoresistive sensor 112.

  The magnetic head 1 is formed on an AlTiC substrate constituting the slider 3 using a thin film forming process. The magnetic head 1 and the slider 3 constitute a head slider. The head slider floats on the magnetic disk 3, and the magnetic disk facing surface 21 is called ABS (Air Bearing Surface). The magnetic head 1 includes a protective film 13 such as alumina around the recording head 12 and the reproducing head 11, and the entire magnetic head 1 is protected by the protective film 13.

  FIG. 2 is a cross-sectional view schematically showing the configuration of the reproducing head 11 of this embodiment. FIG. 2 schematically shows a cross-sectional structure viewed from the ABS surface 21 of the head slider, that is, the air bearing surface facing the magnetic disk 3. The lower side in FIG. 2 is the leading side, and the upper side is the trailing side. In this specification, the AlTiC substrate side on which the reproducing head 11 is formed, that is, the slider 2 side is defined as the lower side, and the trailing side, which is the opposite side, is defined as the upper side. Each layer of the reproducing head 11 is sequentially formed from the lower side. The reproducing head 11 of this embodiment is a CPP reproducing head such as a TMR (Tunneling Magneto Resistance) head or a CPP-MR (Magneto Resistance) head, and the sense current flows in the vertical direction in FIG.

  The magnetoresistive sensor 112 is between the lower shield 111 and the upper shield 113. A distance between the upper surface of the lower shield 111 and the lower surface of the upper shield 113 is shown as a shield interval Gs. The lower shield 111 and the upper shield 113 are made of a conductive magnetic material, function as a magnetic shield, and also serve as a lower electrode and an upper electrode that supply a sense current to the magnetoresistive sensor 112. The lower shield 111 and the upper shield 113 are made of, for example, an alloy containing Ni, Fe, Co, or the like. An upper magnetic isolation film 114 made of a nonmagnetic conductor is formed below the upper shield 113.

  The magnetoresistive sensor 112 is a laminated body composed of a plurality of layers. The magnetoresistive sensor 112 includes a sensor base layer 211, an antiferromagnetic film 212, a fixed layer 213, a nonmagnetic intermediate layer 214, and a free layer 215, which are sequentially stacked from the lower layer side. Each layer is in direct physical contact with an adjacent layer. The sensor underlayer 211 is formed of a nonmagnetic material such as Ta or NiFeCr alloy, and may be formed of a single layer as shown in FIG. The antiferromagnetic film 212 is formed of an antiferromagnetic material such as PtMn.

  The fixed layer 213 in FIG. 2 is a laminated fixed layer, and is composed of a two-layered ferromagnetic film made of a CoFe alloy or the like and a nonmagnetic coupling intermediate layer made of Ru or the like therebetween. The two-layered ferromagnetic film is antiferromagnetically coupled by exchange interaction via the coupling intermediate layer, and the magnetization direction is stabilized. An exchange interaction with the antiferromagnetic film 212 acts on the lower ferromagnetic film, and its magnetization direction is fixed. Note that the fixed layer 213 may have a single-layer structure.

  In the magnetoresistive sensor 112 of this embodiment, the track direction widths of the fixed layer 213 and the antiferromagnetic layer 212 are larger than those of the free layer 215. Further, the junction insulating film 117 and the hard bias film 115 are formed on the fixed layer 213 and the antiferromagnetic layer 211. Thus, by increasing the track direction width of the fixed layer 213 and the antiferromagnetic layer 212, the magnetic stability of these layers can be increased. Note that, like the nonmagnetic intermediate layer 214 in FIG. 2, the upper part of the fixed layer 213 and the upper part of the antiferromagnetic layer 211 are etched so that the lower track width is larger than the free layer 215. Also, the effect of increasing the magnetic stability can be obtained.

  When the reproducing head 11 is a TMR head, the nonmagnetic intermediate layer 214 is formed of an insulator such as magnesium oxide (MgO) and functions as a tunnel barrier. On the other hand, when the reproducing head 11 uses CPP-GMR, the nonmagnetic intermediate layer 214 is formed using a nonmagnetic conductor such as Cu. The free layer 215 is formed of a metal ferromagnetic material such as a NiFe alloy or a CoFe alloy. The free layer 215 can also be a single layer or a laminated structure. The track width of the free layer 215 is indicated by Twf.

  When the relative magnetization direction of the free layer 215 with respect to the magnetization direction of the fixed layer 213 is changed by the magnetic field from the magnetic disk 3, the resistance value (current value) of the magnetoresistive sensor 112 changes. Thus, the reproducing head 11 can detect an external magnetic field. Thus, the reproducing head 11 applies a bias magnetic field to the free layer 215 in order to detect the magnetic field strength from the magnetic disk by the change in the magnetization direction of the free layer 215 relative to the magnetization direction of the fixed layer 213. It is necessary to define the initial state of magnetization. Further, it is required to suppress Barkhausen noise and the like due to magnetic domain nonuniformity of the free layer 215.

  The read head 11 of this embodiment has an in-stack ferromagnetic film 217 that is stacked on the magnetoresistive sensor 112 and generates a bias magnetic field to be applied to the free layer 215. The in-stack ferromagnetic film 217 is formed of a metal such as a NiFe alloy or a CoFe alloy. An in-stack bias intermediate film 216 is disposed between the in-stack ferromagnetic film 217 and the free layer 215. The in-stack bias intermediate film 216 is formed of a nonmagnetic metal such as Ru. The in-stack bias intermediate film 216 controls the exchange coupling force between the in-stack ferromagnetic film 217 and the free layer 215.

  The in-stack ferromagnetic film 217 and the free layer 215 are exchange-coupled via the in-stack bias intermediate film 216. The initial magnetization direction of the free layer 215 is determined by the bias magnetic field of the in-stack ferromagnetic film 217. It also controls the magnetic domain of the free layer 215 and works to make the free layer 215 a single domain. The in-stack ferromagnetic film 217 is a soft magnetic material, and its magnetization direction needs to be fixed in a predetermined direction. Specifically, in order to apply a bias magnetic field in the track width direction (the left-right direction in FIG. 2) of the free layer 215, it is necessary to fix the magnetization direction of the in-stack ferromagnetic film 217 in that direction.

  The reproducing head 11 shown in FIG. 2 has a ferromagnetic film 118 overlying the in-stack ferromagnetic film 217. This ferromagnetic film 118 fixes the magnetization direction of the stacked in-stack ferromagnetic film 217 by transmitting the magnetization of the hard bias film 115. Typically, the ferromagnetic film 118 is formed of a soft magnetic material such as a NiFe alloy or a CoFe alloy. In the structure of FIG. 2, the reproducing head 11 has hard bias films 115 on both the left and right sides of the magnetoresistive sensor 112 (free layer 215) in the track width direction. The hard bias film 115 is made of a hard magnetic material.

  The ferromagnetic film 118 extends over the hard bias film 115 and a part of the ferromagnetic film 118 overlaps the hard bias film 115, and its magnetization is stabilized by the hard bias film 115. Specifically, the ferromagnetic film 118 is in magnetic and physical contact with the hard bias film 115, and is a soft magnetic film by an exchange coupling magnetic field and a generated magnetic field with the hard bias film 115. The magnetization direction of 118 is fixed.

  The ferromagnetic film 118 is in magnetic and physical contact with the in-stack ferromagnetic film 217. The ferromagnetic film 118 whose magnetization direction is fixed fixes the magnetization direction of the in-stack ferromagnetic film 217. As described above, the ferromagnetic film 118 transmits the bias magnetic field of the hard bias film 115 to the in-stack ferromagnetic film 217. Note that the formation of the ferromagnetic film 118 of a hard magnetic material is not excluded. Also in this case, the magnetization of the ferromagnetic film 118 is stabilized by the hard bias film 115, and the ferromagnetic film 118 transmits the bias magnetic field of the hard bias film 115 to the in-stack ferromagnetic film 217.

  By controlling the magnetization direction of the in-stack ferromagnetic film 217 by the hard bias film 115 via the ferromagnetic film 118, the magnetization state of the in-stack ferromagnetic film 217 can be stabilized. The in-stack ferromagnetic film 217 with stabilized magnetic characteristics can stabilize the bias magnetic field that controls the magnetic domain of the free layer 215, and can suppress a decrease in read characteristics. Further, by controlling the magnetization direction of the in-stack ferromagnetic film 217 by the hard bias film 115 on the side of the magnetoresistive sensor 112, the sensor gap Gs between the lower shield 111 and the upper shield 113 can be reduced. .

  Here, since the hard bias film 115 does not generate a bias magnetic field directly applied to the free layer 215, its thickness can be made thinner than that of a normal hard bias film. Thereby, the upper shield 113 can be further flattened, and the step in the track width direction of the upper shield 713 can reduce Usbs. If the upper shield 113 has a deep concave shape on the upper side of the magnetoresistive sensor 112, the effect of the upper shield 113 is reduced by the step Usbs at the end of the magnetoresistive sensor 112, and the reading blur width is increased. Therefore, it is preferable to flatten the upper shield 113 over the free layer track width Tfw. By reducing the thickness of the hard bias film 115 as described above, the upper shield 113 can be flattened and the read characteristics of the read head 11 can be improved.

Here, the reproducing head 11 has a junction insulating film 117 between the magnetoresistive sensor 112 and the hard bias film 115 on both the left and right sides in the track width direction (left and right direction in FIG. Yes. The junction insulating film 117 can be formed of, for example, Al ₂ O ₃ . The junction insulating film 117 electrically insulates between the upper shield film 113 and the lower seal film 111 outside the magnetoresistive sensor 112 and blocks the sense current outside the magnetoresistive sensor 112. The junction insulating film 117 prevents a sense current from flowing between the upper shield film 113 and the lower seal film 111 via the hard bias film 115 without passing through the nonmagnetic intermediate layer 214, and a necessary magnetoresistive sensor. An output of 112 is achieved.

  FIG. 3A is a cross-sectional view of the CPP reproducing head 11 in FIG. 2, and the left side is an ABS (Air Bearing Surface) surface side facing the magnetic disk. The ferromagnetic film 118 extends to the rear side of the reproducing head 11. In addition, the fixed layer 213 (the lower surface thereof) and the antiferromagnetic layer 212 are larger in dimensions than the free layer 215 in the direction perpendicular to the track width direction (direction from the front side to the back side) on the film surface. Yes. This is the same as the dimensional relationship in the track width direction. Only one of the track width direction or the magnetic disk normal direction (direction from the front side to the back side) may satisfy the dimensional relationship.

On the rear side (right side in the drawing) of the magnetoresistive sensor 112, a first rear end insulating film 119 and a second rear end insulating film 129 therebelow exist. These insulating films can also be formed of Al ₂ O ₃ so that the sense current does not flow outside the magnetoresistive sensor 112. A base film 122 of the ferromagnetic film 118 exists between the ferromagnetic film 118 and the first rear end insulating film 119. Note that the backward step difference of the upper shield 113 is indicated by Usbb.

  FIG. 3B shows the positional relationship between the free layer 215 and the hard bias film 115 in the CPP type reproducing head 11. The CPP reproducing head 11 has hard bias films 115 on the left and right sides of the free layer 215 in the track width direction. There is no hard bias film behind the free layer 215, and slits are formed in the track width direction.

  4A and 4B schematically show the magnetization state of each layer in the reproducing head structure shown in FIGS. 2 and 3A. 4A shows a structure in which the reproducing head 11 is viewed from the magnetic disk side as in FIG. 2, and FIG. 4B shows the structure of the reproducing head 11 in the track width direction as in FIG. This corresponds to the cross-sectional structure seen in. As shown in FIG. 4A, the magnetization direction of the ferromagnetic film 118 is fixed in the same direction by the magnetization in the track width direction of the hard bias film 115 on both the left and right sides of the free layer 215 in the track width direction. Further, as shown in FIGS. 4A and 4B, the magnetization of the in-stack ferromagnetic film 217 is fixed in the same direction by the magnetization of the ferromagnetic film 118.

  Between the in-stack ferromagnetic film 217 and the free layer 215 is an in-stack bias intermediate film 216 that is a control film for controlling the direction and strength of the exchange coupling magnetic field. The in-stack ferromagnetic film 217 and the free layer 215 are in magnetic contact via an in-stack bias intermediate film 216 that is a control film for controlling the direction and strength of the exchange coupling magnetic field. That is, the magnetization of the free layer 215 is controlled by the exchange coupling magnetic field via the in-stack bias intermediate film 216. In the example of FIGS. 4A and 4B, the free layer 215 and the in-stack ferromagnetic film 217 are antiferromagnetically coupled, and the magnetization direction of the free layer 215 is the magnetization of the in-stack ferromagnetic film 217. The direction is parallel and opposite.

  The fixed layer 213 includes a lower ferromagnetic layer 311, an upper ferromagnetic layer 313, and an exchange coupling magnetic field control film 312 between them. In the example of FIGS. 4A and 4B, the lower ferromagnetic layer 311 and the upper ferromagnetic layer 313 are antiferromagnetically coupled, and the lower ferromagnetic layer 311 is directed toward the magnetic disk 3. The upper ferromagnetic layer 313 is in a direction away from the magnetic disk 3.

  Here, the hard bias film 115 and the free layer 215 are preferably formed so as not to overlap each other when viewed from the track width direction. That is, in the structure of FIG. 2, as shown there, it is preferable that the height position of the lower surface of the hard bias film 115 is higher than the height position of the upper surface of the free layer 215. More preferably, the height position of the lower surface of the hard bias film 115 substantially coincides with the upper surface of the in-stack ferromagnetic film 217.

  In the reproducing head 11 of this embodiment, the initial magnetization state of the free layer 215 is controlled by an in-stack bias intermediate film 216 formed on the free layer 215. For this reason, it is important that the magnetic field of the hard bias film 115 does not undesirably affect the magnetization state of the free layer 215. By setting the height positions of the hard bias film 115 and the free layer 215 as described above, it is possible to suppress the bias magnetic field of the hard bias film 115 from directly affecting the magnetization state of the free layer 215.

  Next, another preferable reproducing head structure in this embodiment will be described. This reproducing head structure also has a hard bias film made of a hard magnetic material on the back side (the antimagnetic disk side) of the magnetoresistive sensor 112. In this specification, the periphery when the magnetoresistive sensor 112 is viewed from the stacking direction (vertical direction in FIG. 2) is referred to as a side. That is, the left and right sides (both side ends) in the track width direction, the front side (front side) on the ABS side, and the back side (back side) opposite to the ABS side.

  FIG. 5 schematically shows a cross-sectional structure of the reproducing head 11 as viewed from the ABS side of the head slider of this embodiment. FIG. 6A is a cross-sectional view of the CPP reproducing head 11 in FIG. 5, and the left side is an ABS (Air Bearing Surface) surface side facing the magnetic disk. FIG. 6B shows the positional relationship between the free layer 215 and the hard bias films 115 and 125 in the reproducing head 11 in FIG. FIG. 5 corresponds to FIG. 2, and FIGS. 6 (a) and 6 (b) correspond to FIGS. 3 (a) and 3 (b). The description of the same part between them is omitted.

  As shown in FIG. 6A, the reproducing head 11 has a back side hard bias film 125 on the back side of the magnetoresistive sensor 112. The ferromagnetic film 118 extends so as to cover the back side hard bias film 125, and they are in magnetic and physical contact. The function of the back side hard bias film 125 is the same as that of the hard bias film 115.

  That is, the back side hard bias film 125 controls the magnetization state (magnetization direction) of the ferromagnetic film 118. The magnetization direction of the back side hard bias film 125 and the magnetization direction of the hard bias film 115 are the same. Since the hard bias film 115 and the back side hard bias film 125 on both the left and right sides cooperatively control the magnetization state of the ferromagnetic film 118, the magnetization state of the ferromagnetic film 118 can be further stabilized. . Further, as shown in FIG. 5, the presence of the back side hard bias film 125 makes it possible to make the hard bias film 115 thinner. As a result, the step Usbs of the upper shield 113 can be further reduced, and the lead characteristics can be improved.

  As shown in FIG. 6B, the free layer 215 is disposed in the recess of the hard bias film, and the hard bias film surrounds the periphery of the free layer 215 (the magnetoresistive sensor 112) other than the front side. As shown in FIG. 6B, the back side hard bias film 125 and the hard bias film 115 may be formed apart from each other, or these may be formed continuously. Here, in order to reduce the upper shield step, it is preferable to omit the hard bias film 115 at the side end. That is, it is preferable to control the magnetization state of the ferromagnetic film 118 only by the back side hard bias film 125 on the back side. When the free layer track width is Twf and the depth dimension is 100 nm or less, or a narrowing dimension of 100 nm or less, the magnetization state of the ferromagnetic film 118 is controlled only by the back side hard bias film 125 on the back side. Things will be possible. How to form the hard bias film is determined in consideration of the initial state of the free layer 215 and the read characteristics due to other factors.

  FIGS. 7A and 7B schematically show the magnetization state of each layer in the reproducing head 11 shown in FIGS. 5 and 6A. FIGS. 7A and 7B correspond to FIGS. 4A and 4B. The biggest difference between them is the presence of the back side hard bias film 125. As shown in FIGS. 7A and 7B, the magnetization direction of the back side hard bias film 125 is the same as that of the hard bias film 115, and is the direction from left to right in FIG. 7A. ing.

  With reference to FIGS. 8A, 8B, and 8C, the bias magnetic field in each of the conventional read head structure and the read head structure of the two aspects of this embodiment will be described together. 8A shows the conventional head structure, FIG. 8B shows the head structure shown in FIG. 2, and FIG. 8C shows the head structure shown in FIG. In the conventional structure, the initial magnetization Mf of the free layer 215 is defined by the magnetic field Mshb of the hard bias film 115.

  On the other hand, in the head structure of FIG. 2, the magnetization Mthb of the ferromagnetic film 118 is defined by the magnetic field Mshb of the hard bias film 115, and further, the magnetization of the in-stack ferromagnetic film 217 is determined by the magnetization Mthb of the ferromagnetic film 118. Mtf is defined. The anti-ferromagnetic coupling between the in-stack ferromagnetic film 217 and the free layer 215 defines the magnetization Mf of the free layer. In the head structure of FIG. 5, the magnetization Mthb of the ferromagnetic film 118 is defined by the magnetic field Mbhb of the back side hard bias film 125 in addition to the magnetic field Mshb of the hard bias film 115.

  Next, a manufacturing method of the reproducing head of this embodiment will be described with reference to the flowcharts of FIGS. FIG. 9 shows a manufacturing process of the head structure shown in FIG. 2, and FIG. 10 shows a manufacturing process of the head structure shown in FIG. These manufacturing steps are merely examples, and the reproducing head of this embodiment can be formed by other manufacturing methods. First, a manufacturing process of the reproducing head structure shown in FIG. 2 will be described with reference to FIG.

  First, a multilayer film constituting the magnetoresistive sensor 112 is deposited by sputtering (S101). In this step, an in-stack ferromagnetic film 217 and an in-stack bias intermediate film 216 are also formed. Next, the rear end portion of the magnetoresistive sensor 112 is formed. First, the resist depth (dimension in the direction opposite to the magnetic disk from the ABS surface) is determined by resist application and patterning (S102). The rear end portion of the magnetoresistive sensor 112 is formed by ion milling (S103). Further, insulating films 119 and 121 at the rear end of the magnetoresistive sensor 112 are formed (S104), and then the resist is lifted off (S105).

  Subsequently, the shape of the magnetoresistive sensor 112 in the track width direction and other structures are formed. First, a resist track width is formed by resist application and patterning (S106), and a track width of the multilayer magnetoresistive sensor 112 is formed by etching using ion milling (S107). Thereafter, the junction insulating film 117 is formed (S108). Further, a hard bias base film 116 and a hard bias film 115 are formed (S109), and then the resist is lifted off (S110). Next, the ferromagnetic film 118 and the upper shield film 113 are formed. Specifically, the base film 122 and the ferromagnetic film 118 are formed (S111), and further, the upper shield isolation nonmagnetic film 114 is formed (S112). Thereafter, the upper shield film 113 is formed on the upper shield base film (S113).

  Next, a manufacturing process of the head structure shown in FIG. 5 will be described with reference to the flowchart of FIG. A multilayer film constituting the magnetoresistive sensor 112 is deposited by sputtering (S201). In this step, an in-stack ferromagnetic film 217 and an in-stack bias intermediate film 216 are also formed. Next, the shape of the magnetoresistive sensor 112 in the track width direction and other structures are formed. First, a resist track width is formed by resist application and patterning (S202), and a track width of the multilayer magnetoresistive sensor 112 is formed by etching using ion milling (S203). Thereafter, the junction insulating film 117 is formed (S204). Further, a hard bias base film 116 and a hard bias film 115 are formed (S205), and then the resist is lifted off (S206).

  Subsequently, the rear end portion of the magnetoresistive sensor 112 is formed. First, the resist depth (dimension in the direction opposite to the magnetic disk from the ABS surface) is determined by resist application and patterning (S207). The rear end portion of the magnetoresistive sensor 112 is formed by ion milling (S208). Further, insulating films 119 and 121 at the rear end of the magnetoresistive sensor 112 are formed (S209). Thereafter, a base film 126 and a back side hard bias film 125 are formed (S210), and the resist is lifted off (S211).

  Next, the ferromagnetic film 118 and the upper shield film 113 are formed. Specifically, the base film 122 and the ferromagnetic film 118 are formed (S212), and the upper shield isolation nonmagnetic film 114 is further formed (S213). Thereafter, the upper shield film 113 is formed on the upper shield base film (S214).

  Next, the exchange coupling magnetic field via the in-stack bias intermediate film 216 between the in-stack ferromagnetic film 217 and the free layer 215 will be described. FIG. 11 schematically shows the magnetization state of each layer. The in-stack ferromagnetic film 217 has a thickness Ththb, the in-stack bias intermediate film 216 has a thickness Thi, and the free layer 215 has a thickness Thf. The magnetization of the in-stack ferromagnetic film 217 is directed in the same direction by the magnetization of the ferromagnetic film 118. The in-stack ferromagnetic film 217 and the free layer 215 have antiferromagnetic coupling, and the directions of magnetization are opposite to each other.

  12A shows the distribution in the track width direction of the stacked exchange coupling bias magnetic field of the present embodiment, and FIG. 12B shows the distribution in the track width direction of the conventional side edge hard bias magnetic field. It can be seen that the stacked exchange coupling bias magnetic field exhibits flatter characteristics than the side edge hard bias magnetic field. An appropriate bias magnetic field can be applied to the free layer 215 by stabilizing the magnetization of the in-stack ferromagnetic film 217 by the structure of this embodiment.

  Here, if the bias magnetic field to the free layer 215 is too weak, the free layer 215 is not single-domained and noise increases. On the other hand, if the bias magnetic field is too strong, the free layer 215 becomes a magnetic field from the magnetic disk 3. On the other hand, the lead characteristic is deteriorated without changing the direction accurately. The read head 11 of this embodiment includes an in-stack bias intermediate film 216 that controls the exchange coupling magnetic field between the in-stack ferromagnetic film 217 and the free layer 215. The exchange coupling magnetic field between the in-stack ferromagnetic film 217 and the free layer 215 can be adjusted by changing the thickness Thi of the in-stack bias intermediate film 216.

  FIG. 13 shows the relationship between the Ru film thickness and the exchange coupling magnetic field when the in-stack ferromagnetic film 217 and the free layer 215 are formed of an alloy of Co and Fe and Ru is used as the in-stack bias intermediate film 216. An example is shown. As shown in FIG. 13, when the Ru film thickness changes, the strength and direction of the exchange coupling magnetic field change. The film thickness of the in-stack bias intermediate film 216 is selected so that the exchange coupling magnetic field strength is about 0.1 kOe to 0.4 kOe. At this time, both the case where the magnetization of the in-stack ferromagnetic film 217 and the magnetization of the free layer 215 are antiparallel or parallel can be used. Speaking of the parallel case in the example of FIG. 13, the Ru non-magnetic intermediate film thickness is in the range of about 11A to 13A.

  This exchange coupling magnetic field strength is much smaller than the exchange coupling magnetic field strength in the fixed layer 213. As described above, the fixed layer 213 generally has two ferromagnetic layers 311 and 313 that are exchange-coupled. In the fixed layer 213, the film thickness of the intermediate layer is adjusted so that the exchange coupling magnetic field strength is as large as possible. In the example of FIG. 13, for example, the film thickness is in the vicinity of 4A. However, this exchange coupling magnetic field is too strong as a bias magnetic field for the free layer 215. For this reason, the thickness of the in-stack bias intermediate film 216 is increased so that a weaker exchange coupling magnetic field is applied to the free layer.

  Next, another preferred embodiment of the reproducing head structure will be described with reference to FIG. The read head 11 in FIG. 14 has magnetic shield layers 127 on both side ends of the magnetoresistive sensor 112. The magnetic shield layer 127 exists between the junction insulating film 117 and the hard bias film 115. A junction insulating film 117 exists between the magnetic shield layer 127 and the magnetoresistive sensor 112.

  The magnetic shield layer 127 blocks magnetic noise in the track width direction. The magnetic shield layer 127 can be formed of the same soft magnetic material as the shields 111 and 113 in the stacking direction. In the reproducing head structure of this embodiment, since the distance between the hard bias film 115 and the free layer 215 can be increased, there is a problem in terms of the bias magnetic field to the free layer 215 even if the magnetic shield layer 127 is formed. There is nothing.

  Here, the magnetic shield layer 127 is preferably formed of a plurality of interlayer-coupled soft magnetic layers. For example, it is formed of two soft magnetic layers and an intermediate coupling control film between them. By adjusting the interlayer coupling energy, the influence on the free layer 215 can be made very small even when the magnetic shield layer 127 exhibits a shielding function.

  The reproducing head structure of FIG. 14 further includes an amorphous underlayer 128 in addition to the hard bias underlayer 116. The hard bias base film 116 controls the crystal state of the hard bias film 115, while the amorphous base film 117 controls the crystal state of the hard bias base film 116. Since the hard bias film 115 requires a high coercive force and a high magnetic flux density, it is preferable to form the hard bias film 115 with a Co alloy containing Co as a main component, such as CoCrPt. At this time, the saturation magnetic flux density and the like can be adjusted by adjusting the composition of the Co alloy. Also, in order to generate a uniform and strong bias magnetic field with little variation, it is important to control and adjust the polycrystalline orientation state of the Co alloy magnetic film. Here, by forming the hard bias base film 116 from Cr or Cr alloy and adjusting and controlling the orientation state, the polycrystalline orientation of the Co alloy magnetic film as the hard bias film 115 can be controlled.

  The orientation of the hard bias base film 116 made of Cr or Cr alloy can be adjusted and controlled by the amorphous base film 128 that is the base film. Only a specific orientation state of Cr and Co can be realized on the layer of the magnetoresistive sensor multilayer film 112 which is almost a polycrystalline film having a face-centered cubic structure. By selecting the material of the amorphous base film 128, the orientation state of the Co alloy hard bias film 115 can be adjusted and controlled to a desired state.

  As a material for the amorphous base film 128, for example, Ni or Co is used as a base layer to contain an additive element. Examples of the element to be added include P, Cr, Zr, Nb, and Hf. One or more elements are added to Ni or Co to form an amorphous structure. Further, it is important to adjust the surface energy of the amorphous base film 128 by adjusting the oxidation state by oxidation treatment. Note that this structure may be applied to a reproducing head structure of another aspect.

In the following, measurement data relating to the read head structure of the present embodiment is shown. FIG. 15 shows the relationship between the magnetostatic characteristics of the hard bias film and the magnetic film thickness when the underlying film process is changed. ○ is data when “Al ₂ O ₃ / Cr / CoCrPt” is continuously formed, ● is data when “Al ₂ O ₃ / Cr / CoCrPt + etching + 5 nm CoCrPt” is formed, and □ is “Al ₂ O ₃ / Cr + etching + CoCrPt ”is data at the time of film formation. In actual manufacturing, an appropriate structure and value suitable for the head structure are selected.

  FIGS. 16A and 16B show test chip characteristics of a reproducing head to which the structure of the present invention is applied. 16A shows the relationship between the magnetic field of the hard bias film and the magnetization polarity stability, and FIG. 16B shows the relationship between the exchange coupling magnetic field and the magnetic field of the hard bias film. 17A and 17B show the read head read characteristics to which the structure of the present invention is applied. FIG. 17A shows output characteristics, and FIG. 17B shows waveform distortion. By selecting an appropriate range from these measured values, an optimum reproducing head can be designed.

  As mentioned above, although this invention was demonstrated taking the preferable embodiment as an example, this invention is not limited to said embodiment. A person skilled in the art can easily change, add, and convert each element of the above-described embodiment within the scope of the present invention. For example, the stacking order of each layer in the reproducing head is not limited to the above-described bottom spin type, and the present invention is applied to a so-called top spin type head in which the free layer is closer to the substrate side than the fixed layer. Can do. The present invention is particularly useful for a reproducing head of a magnetic disk device, but the present invention can also be applied to other magnetic detection elements. The present invention can be applied to a head in which the dimension of the fixed layer in the track width direction and the disk normal direction is substantially the same as that of the free layer. Also,

In this embodiment, it is sectional drawing which shows the structure of a magnetic head typically. It is sectional drawing which shows typically the structure of the CPP type reproducing head of this embodiment. The cross-sectional structure seen from the ABS surface side of the head slider is schematically shown. A sectional view of the CPP read head of this embodiment and the positional relationship between the free layer and the hard bias film are shown. The cross-sectional view shows a cross-sectional structure in a direction perpendicular to the track width direction on the film surface. In this embodiment, the magnetization state of each layer in the read head structure shown in FIGS. 2 and 3A is schematically shown. It is sectional drawing which shows typically the structure of the CPP type | mold reproducing head of the other aspect of this embodiment. The cross-sectional structure seen from the ABS surface side of the head slider is schematically shown. The sectional view of the CPP type reproducing head of another aspect of this embodiment and the positional relationship between the free layer and the hard bias film are shown. The cross-sectional view shows a cross-sectional structure in a direction perpendicular to the track width direction on the film surface. In another aspect of the present embodiment, the magnetization state of each layer in the reproducing head structure shown in FIGS. 5 and 6A is schematically shown. 2 schematically shows a bias magnetic field in each of a conventional read head structure and a read head structure according to two modes of the present embodiment. 4 is a flowchart showing a manufacturing process of the CPP type reproducing head of the present embodiment. It is a flowchart which shows the manufacturing process of the CPP type | mold reproducing head of the other aspect of this embodiment. It is a figure explaining the exchange coupling magnetic field between an in-stack ferromagnetic film and a free layer, and has shown typically the magnetization state of each layer. FIG. 12A shows the distribution in the track width direction of the stacked exchange coupling bias magnetic field of this embodiment, and FIG. 12B shows the distribution in the track width direction of the conventional side edge hard bias magnetic field. In this embodiment, an example of the relationship between the Ru film thickness and the exchange coupling magnetic field when the in-stack ferromagnetic film and the free layer are formed of an alloy of Co and Fe and Ru is used as the in-stack bias intermediate film Is shown. It is sectional drawing which shows typically the structure of the reproducing head of the other aspect of this embodiment. The cross-sectional structure seen from the ABS surface side of the head slider is schematically shown. FIG. 6 shows the relationship between the magnetostatic characteristics of the hard bias film and the magnetic film thickness when the underlying film process is changed when the structure of the present invention is applied. 2 shows test chip characteristics of a reproducing head to which the structure of the present invention is applied. The read head read characteristic to which the structure of the present invention is applied is shown. FIG. 17A shows output characteristics, and FIG. 17B shows waveform distortion. It is sectional drawing which shows typically the structure of the CPP type reproducing head in a prior art. It is sectional drawing which shows typically the structure of the CPP type reproducing head in a prior art. Of the reproducing head in the prior art It is a flowchart which shows the manufacturing process of the CPP type reproducing head in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetic head, 2 Slider, 3 Magnetic disk, 11 Playback head 12 Recording head, 16 1st junction insulating film, 17 2nd junction insulating film 111 Lower shield, 112 Magnetoresistive sensor, 113 Upper shield 115 Hard bias film, 116 Hard Bias base film 117 Junction insulating film, 118 ferromagnetic film, 119 first rear end insulating film 121 thin film coil, 122 recording magnetic pole, 123 insulator 125 back side hard bias film 127 magnetic shield layer, 128 amorphous base film, 129 Second rear end insulating film 211 Sensor underlayer, 212 Antiferromagnetic film, 213 Fixed layer, 214 Nonmagnetic intermediate layer 215 Free layer, 216 In-stack bias intermediate film, 217 In-stack ferromagnetic film 311 Lower strong Magnetic layer, 312 Exchange coupling magnetic field control Film, 313 upper ferromagnetic layer

Claims (16)

A magnetic lead having a magnetoresistive film having a laminated free layer, a fixed layer, and a nonmagnetic layer between the free layer and the fixed layer, and a current flows in a direction perpendicular to the film surface of the magnetoresistive film・ Head,
An in-stack ferromagnetic film that is stacked on the magnetoresistive film and controls the magnetization state of the free layer by exchange coupling force;
A side ferromagnetic film disposed on a side of the ferromagnetic film and generating a bias magnetic field;
A ferromagnetic film that is laminated in magnetic contact with each of the in-stack ferromagnetic film and the side ferromagnetic film and transmits magnetization to the in-stack ferromagnetic film;
A magnetic read head. The pinned layer, the nonmagnetic layer, and the free layer are sequentially laminated from the base side,
The in-stack ferromagnetic film is disposed on the free layer;
The ferromagnetic film is disposed on the in-stack ferromagnetic film;
The lower surface of the side ferromagnetic film is disposed above the upper surface of the free layer,
The magnetic read head according to claim 1. A lower surface of the side ferromagnetic film substantially coincides with an upper surface of the in-stack ferromagnetic film;
The magnetic read head according to claim 2. The pinned layer, the nonmagnetic layer, and the free layer are sequentially laminated from the base side,
In the track width direction on the film surface or the direction perpendicular to the track width direction, the dimension of the fixed layer is larger than the dimension of the free layer,
The magnetic read head according to claim 1. A magnetic shield film having a soft magnetic layer is disposed in the vicinity of both end portions of the free layer,
The side ferromagnetic film is disposed on the magnetic shield film,
The magnetic read head according to claim 1. The magnetic shield film has a soft magnetic film having a laminated structure of at least two layers having an interlayer coupling structure.
The magnetic read head according to claim 5. The side ferromagnetic film is formed on both sides and back side in the track width direction of the magnetoresistive film,
The magnetic read head according to claim 1. The side ferromagnetic film is formed only on the back side of the magnetoresistive film,
The magnetic read head according to claim 1. The side ferromagnetic film includes a Co alloy film, a Cr alloy base film, and an amorphous alloy seed film that controls the crystal orientation of the base film.
The magnetic read head according to claim 1. A control film for controlling an exchange coupling magnetic field between the in-stack ferromagnetic film and the free layer;
The pinned layer has two soft magnetic layers and a control film that controls an exchange coupling magnetic field between them,
The magnitude of the exchange coupling magnetic field between the in-stack ferromagnetic film and the free layer is smaller than the exchange coupling magnetic field in the fixed layer,
The magnetic read head according to claim 1. A method of manufacturing a magnetic read head in which current flows in a direction perpendicular to the film surface of the magnetoresistive film,
Forming a magnetoresistive film having a laminated free layer, a fixed layer, and a nonmagnetic layer between the free layer and the fixed layer;
An in-stack ferromagnetic film that is laminated on the magnetoresistive film and controls the magnetization state of the free layer by an exchange coupling force;
A side ferromagnetic film that is disposed on the side of the ferromagnetic film and generates a bias magnetic field;
A method of forming a ferromagnetic film that is laminated in magnetic contact with each of the in-stack ferromagnetic film and the side ferromagnetic film to control the magnetization of the in-stack ferromagnetic film. The magnetoresistive film is formed by sequentially laminating the fixed layer, the nonmagnetic layer, and the free layer in this order.
The in-stack ferromagnetic film is disposed on the free layer;
A ferromagnetic film that controls the magnetization of the in-stack ferromagnetic film is disposed on the in-stack ferromagnetic film,
The lower surface of the side ferromagnetic film is disposed above the upper surface of the free layer;
The production method according to claim 11. Forming the side ferromagnetic film such that the lower surface of the side ferromagnetic film substantially coincides with the upper surface of the in-stack ferromagnetic film;
The manufacturing method according to claim 12. From the substrate side, the pinned layer, the nonmagnetic layer, and the free layer are sequentially laminated in order,
Forming the fixed layer and the free layer so that the dimension of the fixed layer is larger than the dimension of the free layer in a track width direction or a direction perpendicular to the track width direction in the film surface;
The manufacturing method according to claim 11. Further forming a magnetic shield film having a soft magnetic layer in the vicinity of both end portions of the free layer,
Forming the side ferromagnetic film on the magnetic shield film;
The manufacturing method according to claim 11. The magnetic shield film has a soft magnetic film having a laminated structure of at least two layers having an interlayer coupling structure.
The manufacturing method according to claim 15.

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