JP2010098137A - Magnetoresistive element, magnetic head, information storage device and magnetic memory - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a magnetoresistive element capable of achieving higher recording density. <P>SOLUTION: The magnetoresistive element includes: a reference layer 143c which is formed with a film of CoFeAlSi added with Ge and/or Cu as a fifth element and has an internal magnetization having a fixed direction; a non-magnetic layer 144 on the reference layer 143c, which is formed with a non-magnetic material; and a free magnetization layer 145 on the non-magnetic layer 144, which is formed with a film of CoFeAlSi added with Ge and/or Cu as a fifth element and has a magnetization having a direction that changes depending on the direction of an external magnetic field. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a magnetoresistive effect element whose electrical resistance value varies depending on the direction of the peripheral magnetic field, a magnetic head for reproducing information using the magnetoresistive effect element, an information storage device equipped with the magnetic head, and the magnetoresistive effect element described above The present invention relates to a magnetic memory that stores information by using the.

  In recent years, magnetoresistive elements have been used in magnetic heads of magnetic storage devices as reproducing elements for reproducing information recorded on magnetic storage media. The magnetoresistive element reproduces information recorded on the magnetic storage medium by using a magnetoresistive effect that converts a change in the direction of the signal magnetic field leaking from the magnetic storage medium into a change in electrical resistance. With the increase in recording density of magnetic storage devices, magnetoresistive elements having a spin valve film have become mainstream. A spin valve film is a so-called laminated ferrimagnetic structure composed of a pinned layer, a nonmagnetic coupling layer, and a reference layer whose magnetization is fixed in a predetermined direction on an antiferromagnetic layer, a nonmagnetic layer laminated thereon, and a magnetic layer. A free magnetic layer whose magnetization direction changes according to the direction and strength of the leakage magnetic field from the storage medium is laminated. The electric resistance value of the spin valve film changes according to the angle formed by the magnetization of the reference layer and the magnetization of the free magnetic layer. The change in the electric resistance value is detected as a voltage change by passing a constant sense current through the spin valve film, so that the magnetoresistive element reproduces the bit recorded in the magnetic storage medium.

  At present, a CPP (Current-Perpendicular-to-Plane) type magnetic head that applies a current in the stacking direction of the magnetoresistive film is applied to the magnetic head.

The output of the CPP type spin valve film is determined by the amount of change in magnetoresistance of a unit area when an external magnetic field is applied to the spin valve film by sweeping the magnetic field from one direction to the opposite direction. The amount of change in magnetoresistance per unit area is obtained by multiplying the amount of change in magnetoresistance (ΔR) of the spin valve film and the area (A) of the film surface of the spin valve film (hereinafter, the amount of change in magnetoresistance is referred to as ΔRA). In order to increase the amount of change in magnetoresistance per unit area, it is necessary to use a material having a large product of the spin-dependent bulk scattering coefficient and the specific resistance for the free magnetic layer and the reference layer. Spin-dependent bulk scattering is a phenomenon in which the degree to which conduction electrons scatter in the magnetic layer of the free magnetic layer or the fixed magnetic layer depends on the spin direction of the conduction electrons, and the larger the spin-dependent bulk scattering coefficient, The amount of change in magnetoresistance increases. As a material having a large spin-dependent bulk scattering coefficient and a large specific resistance, a magnetoresistive effect element using CoFeAl (see Patent Document 1) or CoFeAlSi material with a limited composition has been proposed.
JP2007-88415

  However, in recent years, the demand for higher recording density for hard disk devices and the like has only increased, and even if CoFeAlSi is used for the reference layer and the free magnetic layer, it is difficult to further increase the sensitivity of the CPP type magnetoresistive effect element. It has become.

  In view of the above circumstances, the present case is a magnetosensitive effect element with higher sensitivity, a magnetic head that reproduces information with such high sensitivity, an information storage device equipped with such a magnetic head, and the magnetoresistive effect element described above An object of the present invention is to provide a magnetic memory for storing information by using the.

  The basic form of the magnetoresistive effect element that achieves the above object is a reference layer having a film containing Ge and / or Cu as a fifth element in a CoFeAlSi alloy, the magnetization direction being fixed, and a CoFeAlSi alloy having a first magnetization direction. A nonmagnetic material formed of a nonmagnetic material between a free magnetic layer in which the direction of magnetization containing Ge and / or Cu as five elements changes to a direction according to an external action, and the reference layer and the free magnetic layer And a magnetic layer.

  Here, “the action from the outside” mentioned above means that a magnetic field is applied to the free magnetic layer, or a spin in one of two possible directions of electrons can be taken. This means that a polarized spin current, which is an electron flow consisting only of possessed electrons, flows through the free magnetic layer.

  The basic form of this magnetoresistive effect element is a CPP type magnetoresistive effect element provided with a reference layer, a nonmagnetic layer, and a free magnetic layer. Here, the developer of this case has found that a large specific resistance can be obtained in a film containing Ge and / or Cu as the fifth element in the CoFeAlSi alloy. In order to increase the sensitivity of the CPP type magnetoresistive element, it is necessary to form the free magnetic layer and the reference layer with a material having a large product of a so-called spin-dependent bulk scattering coefficient and a specific resistance. According to the basic form of the magnetoresistive effect element, since the free magnetic layer and the reference layer are formed of a material in which the specific resistance is further increased in the laminated film, the magnetoresistive effect element with higher sensitivity is formed. Is realized.

  In addition, the basic form of the magnetic head that achieves the above-described object is that a reference layer in which the direction of magnetization containing Ge and / or Cu as the fifth element is fixed to the CoFeAlSi alloy is fixed, and Ge and / Or a free magnetic layer in which the direction of magnetization including Cu changes to a direction according to an action from the outside, a nonmagnetic layer formed of a nonmagnetic material between the reference layer and the free magnetic layer, and a stacking direction And a pair of electrodes for flowing current.

  The basic form of this magnetic head is the above-described magnetoresistive element provided with a free magnetic layer and a reference layer formed of a material whose specific resistance is increased, and a magnetic head for reproducing information from the magnetic storage medium. It can be used to reproduce information with higher sensitivity.

The basic form of the information storage device that achieves the above object is a magnetic storage medium, and
A reference layer in which the direction of magnetization including Ge and / or Cu as the fifth element is fixed to the CoFeAlSi alloy, and the direction of magnetization including Ge and / or Cu as the fifth element in the CoFeAlSi alloy according to an external action A magnetic layer including a free magnetic layer that changes in a direction, a nonmagnetic layer formed of a nonmagnetic material between the reference layer and the free magnetic layer, and a pair of electrodes for flowing a current in the stacking direction. A head is provided.

  According to the basic form of this information storage device, since the above-described magnetic head capable of realizing further higher recording density is mounted, it is possible to record information with a larger capacity.

The basic form of the magnetic memory that achieves the above object is as follows:
A reference layer in which the direction of magnetization including Ge and / or Cu as the fifth element is fixed to the CoFeAlSi alloy, and the direction of magnetization including Ge and / or Cu as the fifth element in the CoFeAlSi alloy according to an external action Magnetoresistive effect element comprising a free magnetic layer that changes in a direction, and a nonmagnetic layer formed of a nonmagnetic material between the reference layer and the free magnetic layer, and the free resistance of the magnetoresistive effect element A writing unit is provided to write the information in the free magnetic layer as a magnetization direction by applying an action according to information to the magnetic layer so that the direction of magnetization in the free magnetic layer is directed to the direction according to the information. It is characterized by that.

  Here, also in the basic form of this magnetic memory, the above-mentioned “operation from the outside” means that a magnetic field is applied to the free magnetic layer, or two spin directions that electrons can take. It means that a polarized spin current, which is an electron flow consisting only of electrons having a spin in any one direction, flows through the free magnetic layer.

  According to the basic form of the magnetic memory, information can be recorded using the above-described higher sensitivity magnetoresistive element.

  As described above, according to the present case, the magnetoresistive effect element with higher sensitivity, the magnetic head for reproducing information with such high sensitivity, the information storage device equipped with such a magnetic head, and the above-mentioned A magnetic memory that stores information using a magnetoresistive effect element can be obtained.

  Hereinafter, specific embodiments of the magnetoresistive effect element, the magnetic head, the information storage device, and the magnetic memory described above with reference to the basic form will be described with reference to the drawings.

  First, the first embodiment will be described. The first embodiment is a specific embodiment of a magnetoresistive effect element, a magnetic head, and an information storage device.

  FIG. 1 is a diagram showing a hard disk device corresponding to a specific embodiment of the information storage device described in the basic form.

  The hard disk device 10 shown in FIG. 1 includes a housing 11 and the following components provided in the housing 11.

  Inside the housing 11 is a hub 12 driven by a spindle (not shown), a magnetic disk 13 fixed to the hub 12 and rotated by the spindle, an actuator unit 14, and supported by the actuator unit 14, and the radial direction of the magnetic disk 13 The arm 15 and the suspension 16 are driven by the magnetic head 100 and the magnetic head 100 supported by the suspension 16 is provided. The magnetic disk 13 of this embodiment is a perpendicular magnetic recording type magnetic storage medium in which information is recorded by magnetization in a direction perpendicular to the disk surface, and the magnetic head 100 reproduces information as will be described later. For example, and an inductive recording element for recording information. This inductive recording element is a single pole type element corresponding to the perpendicular magnetic recording system. 1 is also provided with a control circuit 17 for controlling information reproduction by the magnetoresistive effect element in the magnetic head 100 and information recording by the inductive recording element.

  Here, the magnetic disk 13 corresponds to an example of the magnetic storage medium in the basic form described above. The magnetic storage medium in the basic form described above is not limited to a perpendicular magnetic recording type magnetic disk apparatus such as the magnetic disk 13 of the present embodiment. It may be a magnetic storage medium such as an anisotropic magnetic disk or a magnetic tape other than the magnetic disk.

  The magnetic head 100 corresponds to a specific embodiment of the magnetic head described in the basic form. The magnetic head described above for the basic mode is not limited to a magnetic head for perpendicular magnetic recording such as the magnetic head 100 of this embodiment, but may be a magnetic head for in-plane recording.

  Further, the information storage device described above with respect to the basic mode is not limited to the hard disk device having the basic configuration shown in FIG. 1, and records information on a hard disk device having another generally known configuration, for example, a magnetic tape. It may be a device or the like.

  Next, the details of the magnetic head 100 of FIG. 1, which is a specific embodiment of the magnetic head described in the basic mode, will be described.

  FIG. 2 is a diagram showing details of the magnetic head of FIG. 1, which is a specific embodiment of the magnetic head described in the basic form.

  2 is a schematic plan view of the magnetic head 100 of FIG. 1 viewed from the magnetic disk 13 side.

As shown in FIG. 2, a magnetic head 10 is roughly formed on a magnetoresistive effect element 120 formed on a substrate 101 of a head slider made of ceramic such as Al ₂ O ₃ —TiC, and the like. Inductive recording element 130. In FIG. 2, the direction of the arrow X indicates the moving direction of the magnetic disk 13 (see FIG. 1) facing the magnetoresistive element 130. Here, the magnetoresistive effect element 120 corresponds to an example of the magnetoresistive effect element in the basic form described above.

The inductive recording element 130 has an upper magnetic pole 131 having a width corresponding to the track width of the magnetic storage medium in the direction of arrow Y in FIG. 2 and a recording gap layer 132 made of a nonmagnetic material. It consists of an opposing lower magnetic pole 133, a yoke (not shown) connecting the upper magnetic pole 131 and the lower magnetic pole 133, a coil (not shown) for inducing a recording magnetic field by a recording current, and the like. The upper magnetic pole 131, the lower magnetic pole 133, and the yoke are made of a soft magnetic material. Examples of the soft magnetic material include a material having a large saturation magnetic flux density for securing a recording magnetic field, such as Ni ₈₀ Fe ₂₀ , CoZrNb, FeN, FeSiN, FeCo, and CoNiFe. The magnetic head described above with respect to the basic form is not limited to the form provided with the inductive recording element 130 of the present embodiment, but is provided with an inductive recording element having another generally known structure. May be.

  At the time of information recording, a recording current whose polarity sequentially changes according to information is caused to flow through the coil of the inductive recording element 130 by the control circuit 17 of FIG. As a result, a recording magnetic field whose direction changes according to information is induced by the coil. A recording magnetic field is applied to the surface of the magnetic disk 13 of FIG. In the magnetic disk 13 that has been applied with the recording magnetic field, the magnetization is directed to either the front or back side of the magnetic disk 13 depending on the direction of the applied recording magnetic field.

  Here, at the time of information reproduction, the magnetic disk 13 is rotated, and the magnetic disk 13 passes just below the magnetic head 100. As a result, information is recorded on the magnetic disk 13 as an array of a plurality of magnetizations each facing either the front or back depending on the information to be recorded.

  The magnetoresistive effect element 120 has a configuration in which a lower electrode 121, a magnetoresistive effect film 140, an alumina film 125, and an upper electrode 122 are laminated on an alumina film 102 formed on the surface of a substrate 101. The magnetoresistive film 140 is electrically connected to the lower electrode 121 and the upper electrode 122, respectively.

  Here, each of the lower electrode 121 and the upper electrode 122 corresponds to an example of an electrode in the basic form of the magnetic head or the information storage device described above.

  On both sides of the magnetoresistive effect film 140, a magnetic domain control film 124 is provided via an insulating film 123. The magnetic domain control film 124 is made of, for example, a laminate of a Cr film and a ferromagnetic CoCrPt film. The magnetic domain control film 124 makes a free magnetic layer, which will be described later, constituting the magnetoresistive effect film 140 a single magnetic domain and prevents the occurrence of Barkhausen noise. The lower electrode 121 and the upper electrode 122 have a function as a magnetic shield in addition to a function as a flow path of the sense current Is. Therefore, the lower electrode 121 and the upper electrode 122 are made of a soft magnetic alloy such as NiFe or CoFe. Furthermore, as described above, in this embodiment, the magnetoresistive film 140 is electrically connected directly to the lower electrode 121, but a conductive film is formed at the interface between the magnetoresistive film 140 and the lower electrode 121. For example, a Cu film, a Ta film, a Ti film, or the like may be provided.

  In the magnetic head 100 of FIG. 2, although not shown, the magnetoresistive effect element 120 and the inductive recording element 13 are covered with an alumina film or the like to prevent corrosion or the like.

  At the time of information reproduction, the magnetic disk 13 is rotated, and an array of magnetizations each oriented in accordance with the information passes immediately below the magnetic head 100, and the magnetoresistive effect film 140 is electrically driven according to the direction of the medium magnetic field. The resistance value changes. Hereinafter, the electric resistance value that changes according to the direction of the medium magnetic field is referred to as a magnetoresistance value. At the time of information reproduction, in the magnetoresistive effect film 140, the change in magnetoresistance value according to the direction of the magnetic field from each magnetization that sequentially passes directly under the magnetic head 100, that is, according to the information carried by each magnetization. Will occur.

  Here, at the time of information reproduction, a sense current Is that flows from the upper electrode 122 to the lower electrode 121 through the magnetoresistive effect film 140 flows through the magnetoresistive effect element 120 by the control circuit 17 of FIG. In the control circuit 17, a change in the magnetoresistance value of the magnetoresistive effect film 140 is detected as a voltage change when the sense current Is flows. That is, the control circuit 17 detects a change in the magnetoresistance value corresponding to the information recorded on the magnetic disk 13 as this voltage change. In the present embodiment, information reproduction using the magnetoresistive effect element 120 is executed in this way. The direction in which the sense current Is flows is not limited to the direction shown in FIG. Further, the moving direction of the magnetic disk 13 may be opposite to the direction of the arrow X shown in FIG.

  FIG. 3 is a cross-sectional view of the magnetoresistive film shown in FIG.

  As shown in FIG. 3, the magnetoresistive film 140 includes an underlayer 141, an antiferromagnetic layer 142, a fixed magnetization stack 143, a nonmagnetic layer 144, a free magnetization layer 145, and a protective layer 146 sequentially stacked. It has a so-called single spin valve structure.

  Here, the free magnetic layer 145 corresponds to an example of the free magnetic layer in the basic form described above, and the nonmagnetic layer 144 corresponds to an example of the nonmagnetic layer in the basic form.

  The underlayer 141 is formed on the surface of the lower electrode 121 shown in FIG. The underlayer 141 may be, for example, a NiCr or Ru layer, or a Ta film (for example, a film thickness of 5 nm), a NiFe film (for example, a film thickness of 5 nm), a Ta film (for example, a film thickness of 5 nm). And a Ru film (for example, a film thickness of 5 nm) or the like. When the underlayer 141 is a stacked body of a Ta film and a NiFe film, the NiFe film in the stacked body preferably has a Fe content in the range of 17 atomic% to 25 atomic%. By using the NiFe film having such a composition, the antiferromagnetic layer 142 is epitaxially grown on the (111) crystal plane which is the crystal growth plane of the NiFe film. Thereby, the crystallinity of the antiferromagnetic layer 142 can be improved.

  The antiferromagnetic layer 142 has a film thickness in the range of 4 nm to 30 nm (preferably 4 nm to 10 nm), and Mn—TM alloy (TM is at least one of Pt, Pd, Ni, Ir, and Rh). It is a layer comprised from. Examples of the Mn-TM alloy include PtMn, PdMn, NiMn, IrMn, and PtPdMn. The antiferromagnetic layer 142 plays a role of fixing the magnetization in the pinned layer 143a in a predetermined direction by causing an exchange interaction with the pinned layer 143a of the fixed magnetization stack 143 to be described later.

  The fixed magnetization stack 143 has a so-called stacked ferrimagnetic structure in which a pinned layer 143a, a nonmagnetic coupling layer 143b, and a reference layer 143c are stacked in this order from the antiferromagnetic layer 142 side. Here, in the magnetoresistive effect element 120 of this embodiment, the reference layer 143 c in the magnetoresistive effect film 140 is disposed on the base 101 side with respect to the free magnetic layer 145, that is, on the lower layer side of the free magnetic layer 145. The magnetoresistive effect element has a so-called bottom type spin valve structure.

  In the fixed magnetization stack 143, the pinned layer 143a and the reference layer 143c are antiferromagnetically exchange-coupled, and as a result, the magnetization directions of the layers are antiparallel to each other. As a result, the magnetic field generated by the magnetization of the reference layer 143c is canceled by the magnetic field generated by the magnetization of the pinned layer 143a, and the magnetic field applied to the free layer is suppressed and the magnetoresistive effect is increased.

This is different from the basic form described above.
“The direction of magnetization formed of a magnetic material on the opposite side of the reference layer to the nonmagnetic layer side is in a second direction opposite to the first direction in which the magnetization of the reference layer is to be fixed. A pinned layer that is fixed,
By antiferromagnetically coupling the magnetization of the pinned layer and the magnetization of the reference layer formed between the pinned layer and the reference layer, the magnetization in the reference layer is changed to the first direction. This means that an application form of “having a laminated ferrimagnetic structure including a nonmagnetic coupling layer made of a nonmagnetic material and fixed to the substrate” is preferable.

  The pinned layer 143a corresponds to an example of the pinned layer in this application mode, and the nonmagnetic coupling layer 143b corresponds to an example of the nonmagnetic coupling layer in this application mode.

  The antiferromagnetic layer 142 corresponds to an example of the antiferromagnetic layer in this application mode.

The pinned layer 143a is made of a soft magnetic material. Examples of the soft magnetic material suitable for forming the pinned layer 143a include Co ₆₀ Fe ₄₀ and NiFe in terms of low specific resistance. In the present embodiment, the pinned layer 143a and the reference layer 143c are antiferromagnetically exchange-coupled as described above. As a result, the magnetization of the pinned layer 143a is opposite to the magnetization direction of the reference layer 143c, so that the pinned layer 143a acts in a direction to reduce the magnetoresistance change ΔRA in the magnetoresistive effect film 140. For this reason, by forming the pinned layer 143a with a soft magnetic material having a low specific resistance as described above, it is possible to suppress a decrease in the magnetoresistance change ΔRA.

The reference layer 143c is a Co _a Fe _b Al _c Si _d having _a film thickness in the range of 1 to 10 nm (where 50 ≦ a ≦ 70, 10 ≦ b ≦ 25, 15 ≦ c ≦ 35, 0 < d <35 (at%)) in a film prepared by a composition range of Ge or _{Cu (Co a Fe b Al c} Si d) (100-X) M X as a fifth element. Here, M represents Ge and / or Cu, and the composition X is an alloy to which 0 <X <20 (at%) is added. The element added to CoFeAlSi may be Ge, Cu, or an alloy of Ge and Cu.

In addition, the reference layer in the above-mentioned basic form is not limited to the one composed only of the quinary alloy layer such as the reference layer 143c of the present embodiment. For example, the above-described film, Co, Ni, Fe It may be a laminated film with a layer formed of an alloy made of two or more kinds of other magnetic elements. In the case of such a laminated film, the type and composition ratio of the above-mentioned magnetic elements may be different for the latter layer, and not only the upper and lower sides of the reference layer 143c are laminated, but also both above and below. May be stacked. In addition, the ternary alloy (Co _a Fe _b Al _c Si _d ) _(100-X) M _X (where 50 ≦ a ≦ 70, 10 ≦ b ≦ 25, 15 ≦ c ≦ 35, 0 <d <35 , 0 <X <20 (at%), M = Ge, Cu) may be formed by sputtering one target made of an alloy of five kinds of metals, and simultaneously sputtering five targets for each element. Film formation and multilayer film formation may be performed, or simultaneous film formation and multilayer film formation of an alloy target in which two, three, or four of five kinds of elements are combined may be used.

  The nonmagnetic coupling layer 143b has a thickness in a range where the pinned layer 143a and the reference layer 143c are exchange-coupled antiferromagnetically. The range is 0.4 nm to 1.5 nm (preferably 0.4 nm to 0.9 nm). The nonmagnetic coupling layer 143b is made of a nonmagnetic material such as Ru, Rh, Ir, Ru-based alloy, Rh-based alloy, or Ir-based alloy. As the Ru-based alloy, an alloy in which any one of Co, Cr, Fe, Ni, and Mn is added to Ru, an alloy in which these alloys are added to Ru, or the like is preferable.

  The nonmagnetic layer 144 is a nonmagnetic layer having any film thickness within a range of 1.5 nm to 10 nm. Suitable materials for the nonmagnetic layer 144 include Cu, Al, Cr, TiO, MgO, ZnO, and the like.

Free magnetic layer 145, similarly to the reference layer 143c, with either film having a thickness _{(Co a Fe b Al c Si} d) (100-X) composition range of _{M X} in the range of 1~10nm This is a produced film. Here, M represents Ge and / or Cu, and the composition X is an alloy to which 0 <X <20 (at%) is added. The element added to CoFeAlSi may be a film of Ge, Cu, or an alloy of Ge and Cu.

The free magnetic layer in the basic form described above is not limited to a quinary alloy layer such as the free magnetic layer 145 of the present embodiment. For example, the above-described film and Co, Ni A laminated film with a layer formed of an alloy made of two or more kinds of magnetic elements among other magnetic elements such as Fe and Fe. In the case of such a laminated film, the type and composition ratio of the above-mentioned magnetic elements may be different for the latter layer, and not only the upper and lower sides of the reference layer 143c are laminated, but also both above and below. May be stacked. Further, similarly to the reference layer, the present ternary alloy (Co _a Fe _b Al _c Si _d ) _(100-X) M _X (where 50 ≦ a ≦ 70, 10 ≦ b ≦ 25, 15 ≦ c ≦ 35) , 0 <d <35, 0 <X <20 (at%), M = Ge, Cu) may be formed by sputtering one target made of an alloy of five kinds of metals. Five targets may be simultaneously sputtered and stacked, or a combination of two, three, or four of five elements may be simultaneously formed and stacked.

  Here, the reason why the film in which Ge or Cu is added as the fifth element to the CoFeAlSi alloy as described above is used for forming the reference layer 143c and the free magnetic layer 145 for the following reason.

  The developer of this case has found that such an alloy film can obtain a higher specific resistance than the conventional one, as shown in the following figure.

FIG. 4 is a graph showing the specific resistance of a single film when Ge is added as a fifth element to a CoFeAlSi alloy on a SiO ₂ substrate.

Here, in the example of FIG. 4, the CoFeAlSi alloy film is made of an alloy having a composition of Co at 50 at%, Fe at 25 at%, Al at 12.5 at%, and Si at 12.5%. And (Co ₅₀ Fe ₂₅ Al _12.5 Si _12.5 ) _(100-X) Ge _X shows the composition of Ge. From the graph of FIG. 4, the specific resistance of the alloy film in which Ge is added to the CoFeAlSi alloy with respect to the single layer film of the CoFeAlSi alloy increases as the composition of Ge increases. In the graph of FIG. 4, when the composition X of the Ge film is about 15%, the specific resistance of the single layer film of CoFeAlSi alloy is about three times.

  In general, the magnetoresistance change ΔRA in the magnetoresistive effect film depends on the product of the spin-dependent bulk scattering coefficient representing the degree of conduction electron scattering in the free magnetic layer and the reference layer and the specific resistance.

  In the present embodiment, a large magnetoresistance change ΔRA in the magnetoresistive film 140 is realized by forming the free magnetic layer 145 and the reference layer 143c with the laminated film as described above and increasing the specific resistance. During information reproduction, the voltage change according to the recorded information when the sense current Is flows through the magnetoresistive effect element 120 depends on the magnetoresistive change amount ΔRA of the magnetoresistive effect film 140. In this embodiment, the reproduction sensitivity in information reproduction is improved by increasing the specific resistance in the free magnetic layer 145 and the reference layer 143c.

  The protective layer 146 plays a role of preventing the free magnetic layer 145 from being oxidized during the heat treatment described later for causing the antiferromagnetic property of the antiferromagnetic layer 142 to appear when the magnetoresistive film 140 is formed. It is made of a magnetic conductive material. Examples of the nonmagnetic conductive material include metals including any of Ru, Cu, Ta, Au, Al, and W. In this embodiment, the protective layer 146 is a single-layer film of such a metal, but the protective layer that serves to prevent oxidation as described above is not limited to a single-layer film. A laminated film in which these films are laminated may also be used.

  Next, a method for forming the magnetoresistive film 140 shown in FIG. 3 will be described.

  First, the layers from the base layer 141 to the protective layer 146 are formed using the materials described above by sputtering, vapor deposition, CVD, or the like.

  Next, the laminate thus obtained is heat-treated in a magnetic field. The heat treatment is performed in a vacuum atmosphere under conditions of a heating temperature of 250 ° C. to 320 ° C., a heating time of about 2 to 4 hours, and an applied magnetic field of 1592 kA / m. By this heat treatment, a part of the Mn-TM alloy described above is ordered, and antiferromagnetism appears in the antiferromagnetic layer 142. Further, by applying a magnetic field in a predetermined direction during the heat treatment, the magnetization direction of the antiferromagnetic layer 142 is set to that direction, and as a result, the exchange interaction between the antiferromagnetic layer 142 and the pinned layer 143a. Thus, the magnetization of the pinned layer 143a is fixed in a predetermined direction.

  Next, the laminate from the base layer 141 to the protective layer 146 is patterned into a shape as shown in FIG.

  The magnetoresistive film 140 thus formed has a large magnetoresistance change ΔRA as described above, and as a result, the reproduction sensitivity of the magnetic head 100 is improved. In the hard disk device 10 of the present embodiment shown in FIG. 1, the recording density is further increased by using the magnetic head 100 with high reproduction sensitivity, and information recording and information reproduction with a large capacity can be realized. It is possible.

  Hereinafter, the present case will be described more specifically based on examples corresponding to the first embodiment described above. However, the present case is not limited to the following examples.

[First embodiment]
A magnetoresistive effect element having the configuration of the magnetoresistive effect film shown in FIG. 3 and having a reference layer and a free magnetic layer made of an alloy obtained by adding Ge to a CoFeAlSi alloy was manufactured by the following method.

First, a Cu (250 nm) / NiFe (50 nm) laminated film is formed as a lower electrode on a silicon substrate on which a thermal oxide film is formed from the silicon substrate side, and then an underlayer having the following composition and film thickness: Each layer of the laminate up to the protective layer was formed at room temperature using a sputtering apparatus in an ultrahigh vacuum (degree of vacuum: 2 × 10 ⁻⁶ Pa or less) atmosphere.

  Next, heat treatment was performed to make the antiferromagnetic layer appear antiferromagnetic. The heat treatment conditions were a heating temperature of 300 ° C., a treatment time of 3 hours, and an applied magnetic field of 1952 kA / m.

Then, in this way it was obtained the laminate performs fine processing by photolithography and ion milling, each of the CPP-GMR element, having six junction area in the range of 0.1μm ² ~0.6μm ² Forty pieces were produced in area.

  The specific configuration of the magnetoresistive film of the first embodiment is shown below. The numerical value in parentheses represents the film thickness.

Underlayer: Ru (4 nm)
Antiferromagnetic layer: IrMn (5 nm)
Pinned layer: Co ₆₀ Fe ₄₀ (4 nm)
Nonmagnetic coupling layer: Ru (0.7 nm)
Reference layer: (Co ₅₀ Fe ₂₅ Al _12.5 Si _12.5 ) _(100-X) Ge _X (0 ≦ X ≦ 20 at%) (3.0 nm)
Nonmagnetic layer: Cu (3.5 nm)
Free magnetic layer: (Co ₅₀ Fe ₂₅ Al _12.5 Si _12.5 ) _(100-X) Ge _X (0 ≦ X ≦ 20 at%) (4.0 nm)
Protective layer: Ru (5 nm)
And about the sample which changed the composition, magnetoresistive change amount (DELTA) RA was measured and the 40 element average of MR ratio ((DELTA) RA / RA) which is a magnetoresistive change rate was calculated | required.

  The magnetoresistance change ΔRA was measured as follows.

  First, the current value of the sense current is set to 2 mA, an external magnetic field is applied in parallel with the magnetization direction of the reference layer, and the strength of the external magnetic field is changed in a range of −79 kA / m to 79 kA / m, The magnetoresistance curve was obtained by measuring the voltage between the upper electrode and the upper electrode with a digital voltmeter. Then, the magnetoresistance change ΔRA was obtained from the difference between the maximum value and the minimum value of the magnetoresistance curve.

  Further, Hin and Hc described later were obtained from hysteresis of a magnetoresistance curve obtained by applying an external magnetic field in the same direction as described above and changing the intensity in a range of −7.9 kA / m to 7.9 kA / m. .

  FIG. 5 is a diagram showing a magnetoresistance curve.

  Hin represents the shift amount of the magnetic field to which the resistance value change responds when the direction of the external magnetic field is changed as shown in FIG. When the magnetic coupling force between the reference layer and the free magnetic layer is broken, the shift amount represented by Hin becomes small, and the magnetization of the free magnetic layer can respond to changes in the external magnetic field with high sensitivity, and the direction of the external magnetic field The change is immediately detected as a change in resistance value. That is, from the viewpoint of the sensitivity of the magnetoresistive effect element, it is preferable that this Hin is small.

  This Hin is mainly determined by the film thickness and roughness of the nonmagnetic layer. The smaller the film thickness of the nonmagnetic layer or the greater the roughness, the more the reference layer and the free magnetic layer are partially magnetically coupled. End Hin becomes large. In general, it is often difficult to control roughness when forming a nonmagnetic layer, and Hin is reduced by increasing the film thickness of the nonmagnetic layer. On the other hand, in the magnetoresistive effect element, the increase in the film thickness of the nonmagnetic layer causes an increase in the distance between the upper terminal and the lower terminal, resulting in a decrease in the efficiency in the bit direction. From the viewpoint of the efficiency in the bit direction, the film thickness of the nonmagnetic layer is desirably 3.5 nm or less. In order to function normally as a magnetoresistive effect element, Hin is required to satisfy at least Hin ≦ 10 Oe.

  Hc is the coercive force, and indicates the width of the hysteresis loop as shown in FIG. In order to reverse the magnetization in the free magnetic layer with high sensitivity to an external magnetic field, the smaller this Hc, the better. Hc is preferably Hc ≦ 10 Oe.

[Second Embodiment]
The magnetoresistive effect element was created under the same conditions as in the first embodiment, except that the reference layer and the free magnetic layer were formed by adding Cu as the fifth element to the CoFeAlSi alloy. Magnetoresistance value change rate MR ratio, Hin, and Hc were determined.

  FIG. 6 is a graph showing the magnetoresistance value change rate MR ratio for the first and second examples, FIG. 7 is a graph showing Hin for the first and second examples, and FIG. It is a graph which shows Hc about the 1st and 2nd example.

  In the graph of FIG. 6, the composition of Ge and Cu is taken on the horizontal axis, and the MR ratio is taken on the vertical axis. In the graph of FIG. 7, the composition of Ge and Cu is taken on the horizontal axis, and the vertical axis is taken. Hin is taken, and in the graph of FIG. 8, the horizontal axis represents the composition of Ge and Cu, and the vertical axis represents Hc. In each graph, the first example is indicated by a solid line connecting the plotted points indicated by square marks, and the second example is indicated by a solid line connecting the plotted points indicated by diamonds.

  From the graph of FIG. 6, the MR ratio is increased by forming the reference layer and the free magnetic layer with the alloy film to which the fifth element is added as described above, and when Ge is added (first embodiment), Ge Is approximately 18 at%, and an MR ratio of 7.8%, which is 40% or more larger than the MR ratio of the single layer film of the CoFeAlSi alloy, can be realized. When Cu is added (second embodiment), the Cu composition Is about 8%, and it was confirmed that MR ratio = 6.0% can be realized. From this, it can be seen that the MR ratio can be increased by the laminated film as described above.

  Further, from the graphs of FIGS. 7 and 8, it was confirmed that when Ge was added (first example), the above desirable value of 10 Oe or less could be realized for both Hin and Hc. In addition, when Cu was added (second example), it was first confirmed that a desirable value of 10 Oe or less can be realized for Hin. As for Hc, the Cu composition reaches 10 Oe at 12 at%. Here, when the magnetoresistive effect element is applied to a magnetic head, it has been found that if Hc is 15 Oe or less in practical use, it can be used without any problem. Hc in the second embodiment has no practical problem. It is within the range.

  As described above with reference to the examples, according to the magnetoresistive film 140 of the first embodiment shown in FIG. 3, a large magnetoresistive change with an increase in specific resistance is realized. The high read sensitivity of the magnetic head 100 according to the first embodiment shown in FIG. 2 that includes the magnetoresistive effect element 120 including the effect film 140 as a read element is realized. As a result, in the hard disk device 10 of the first embodiment shown in FIG. 1, by using the magnetic head 100 with high reproduction sensitivity, further higher recording density is realized, and information recording and information reproduction with a large capacity are possible. It is possible.

  Next, a second embodiment will be described. This second embodiment is also a specific embodiment of a magnetoresistive effect element, a magnetic head, and an information storage device. However, the second embodiment is different from the first embodiment in the configuration of the magnetoresistive film. Hereinafter, the second embodiment will be described focusing on the differences from the first embodiment described above.

  FIG. 9 is a cross-sectional view of the magnetoresistive film of the second embodiment.

  In FIG. 9, the same components as those of the magnetoresistive film 140 of the first embodiment shown in FIG. 3 are denoted by the same reference numerals as those in FIG. The duplicate description of is omitted.

  As shown in FIG. 9, the magnetoresistive film 150 includes an underlayer 141, a free magnetic layer 151, a nonmagnetic layer 152, a fixed magnetization stack 153, an antiferromagnetic layer 154, and a protective layer 146 that are sequentially stacked. It has a single spin valve structure. The fixed magnetization stack 153 has a stacked ferrimagnetic structure in which a reference layer 153c, a nonmagnetic coupling layer 153b, and a pinned layer 153a are stacked in this order from the nonmagnetic layer 152 side. The free magnetic layer 151 of the present embodiment corresponds to an example of the free magnetic layer in the basic form described above, and the nonmagnetic layer 152 of the present embodiment corresponds to an example of the nonmagnetic layer in the basic form of the present embodiment. The reference layer 153c corresponds to an example of a reference layer in its basic form.

  Here, in the magnetoresistive effect element according to the second embodiment, as shown in FIG. 9, in the magnetoresistive effect film 150, the reference layer 153c is opposite to the base with respect to the free magnetic layer 151, that is, free magnetization. This is a magnetoresistive element having a so-called top-type spin valve structure, which is disposed on the upper layer side of the layer 151.

  Also in this embodiment, the free magnetic layer 151 and the reference layer 153c are formed of a film obtained by adding Ge or Cu as a fifth element to a CoFeAlSi alloy, like the magnetoresistive film 140 of the first embodiment shown in FIG. The magnetoresistive film 150 in FIG. 9 has a large magnetoresistance change ΔRA for the same reason as in the magnetoresistive film 140 in FIG.

  The method for forming the magnetoresistive film 150 is substantially the same as the method for forming the magnetoresistive film 140 shown in FIG. Further, since the evaluation of the magnetoresistive effect film 140 shown in FIG. 3 can be applied to the magnetoresistive effect film 150 shown in FIG. 8, the magnetoresistive effect film 150 shown in FIG. Description is omitted.

  Next, a third embodiment will be described. The third embodiment is also a specific embodiment of the magnetoresistive effect element, the magnetic head, and the information storage device. However, this third embodiment differs from the first and second embodiments in the configuration of the magnetoresistive film. Hereinafter, the third embodiment will be described focusing on this difference.

  FIG. 10 is a cross-sectional view of the magnetoresistive film of the third embodiment.

  In FIG. 10, the same components as those of the magnetoresistive film 140 according to the first embodiment shown in FIG. 3 are denoted by the same reference numerals as those in FIG. The duplicate description of is omitted. 3 are substantially the same as the components in FIG. 3, but for convenience of explanation, components whose names have been changed from those in FIG. 3 are given the same reference numerals as those in FIG. In the following, redundant description of these substantially equivalent components is also omitted.

  10 includes an underlayer 141, a lower antiferromagnetic layer 142 ′, a lower fixed magnetization stack 143 ′, a lower nonmagnetic layer 144 ′, a free magnetic layer 145, an upper nonmagnetic layer 164, The upper fixed magnetization stack 163, the upper antiferromagnetic layer 162, and the protective layer 146 are sequentially stacked. That is, the magnetoresistive film 160 includes an upper nonmagnetic layer 164, an upper fixed magnetization stack 163, and an upper antiferromagnetic layer between the free magnetic layer 145 and the protective layer 146 of the magnetoresistive film 140 shown in FIG. 162 has a so-called dual spin valve structure.

  The upper nonmagnetic layer 164 and the upper antiferromagnetic layer 162 are each formed of the same material as the lower nonmagnetic layer 144 'and the lower antiferromagnetic layer 142', and have the same film thickness.

  Further, the lower pinned magnetization stack 143 ′ has a stacked ferrimagnetic structure in which a lower pinned layer 143a ′, a lower nonmagnetic coupling layer 143b ′, and a lower reference layer 143c ′ are stacked in this order from the base layer 141 side. . Furthermore, the upper pinned magnetization stack 163 has a stacked ferrimagnetic structure in which an upper pinned layer 163a, an upper nonmagnetic coupling layer 163b, and an upper reference layer 163c are stacked in this order from the upper antiferromagnetic layer 162 side. . The upper pinned layer 163a, the upper nonmagnetic coupling layer 163b, and the upper reference layer 163c are formed of the same material as the lower pinned layer 143a ′, the lower nonmagnetic coupling layer 143b ′, and the lower reference layer 143c ′, respectively. Has a similar film thickness.

  In the magnetoresistive film 160 of FIG. 10, the upper reference layer 163c, the lower reference layer 143c ′, and the free magnetic layer 145 are made of a fifth element in a CoFeAlSi alloy, like the magnetoresistive film 140 of the first embodiment shown in FIG. As a film to which Ge or Cu is added. Accordingly, the magnetoresistive effect film 160 of FIG. 10 has a large magnetoresistance change ΔRA for the same reason as the magnetoresistive effect film 140 of FIG.

  Further, the magnetoresistive film 160 includes a spin valve structure including a lower fixed magnetization stack 143 ′, a lower nonmagnetic layer 144 ′, and a free magnetic layer 145, a free magnetic layer 145, an upper nonmagnetic layer 164, and an upper fixed magnetization. It has two spin valve structures, that is, a spin valve structure made of a stacked body 163. Therefore, the magnetoresistive effect film 160 doubles the magnetoresistive change amount ΔRA, and the value is about twice the magnetoresistive change amount ΔRA of the magnetoresistive effect film 140 of FIG. As a result, by using the magnetoresistive effect film 160 of FIG. 10 as the magnetoresistive effect element, it is possible to realize a magnetoresistive effect element with higher sensitivity than when the magnetoresistive effect film 140 of FIG. 3 is used.

This realizes the dual spin valve structure as described above with respect to the basic form described above.
“A second nonmagnetic layer formed of a nonmagnetic material on the side opposite to the nonmagnetic layer side of the free magnetic layer;
A second reference layer formed on a side opposite to the free magnetic layer side of the second nonmagnetic layer and having a magnetization direction fixed to the same direction as the magnetization direction in the reference layer. The application form is suitable,
For this application,
“The second reference layer is formed of a magnetic material on the opposite side of the second nonmagnetic layer, and the direction of magnetization is such that the magnetization in the second reference layer should be fixed. A second pinned layer fixed in a second orientation opposite to the orientation;
Antiferromagnetically coupling the magnetization in the second pinned layer and the magnetization in the second reference layer formed between the second pinned layer and the second reference layer. And a second non-magnetic coupling layer made of a non-magnetic material that fixes the magnetization in the second reference layer in the first direction is more preferable.
For this more preferred application,
“The second pinned layer is formed of an antiferromagnetic material on the side opposite to the second nonmagnetic coupling layer side, and the magnetization direction in the second pinned layer is fixed to the second direction. This means that the application form “with a second antiferromagnetic layer” is more preferable.

  The upper nonmagnetic layer 164 in the present embodiment corresponds to an example of the second nonmagnetic layer in the application mode described above, and the upper reference layer 163c corresponds to an example of the second reference layer in the application mode. The pinned layer 163a corresponds to an example of the second pinned layer in this application mode, and the upper nonmagnetic coupling layer 163b corresponds to an example of the second nonmagnetic coupling layer in this application mode, and the upper antiferromagnetic layer 162 corresponds to an example of a second antiferromagnetic layer in this application mode.

  The method for forming the magnetoresistive film 160 is substantially the same as the method for forming the magnetoresistive film 140 shown in FIG. 3 can be applied to the magnetoresistive film 160 of FIG. 10 as well, and therefore, the embodiment of the magnetoresistive film 160 of FIG. 10 is also applicable. Description is omitted.

  Next, a fourth embodiment will be described. The fourth embodiment is a specific embodiment of the magnetoresistive effect element and magnetic memory described in the basic form.

  FIG. 11 is a diagram showing a magnetic memory according to the fourth embodiment, and FIG. 12 is a diagram showing an equivalent circuit of the magnetic memory shown in FIG.

  The magnetic memory 20 of the present embodiment is configured by arranging a plurality of memory cells 200 each storing information corresponding to 1 bit in a matrix. In the magnetic memory 20 of the present embodiment, a magnetoresistive film equivalent to the magnetoresistive film 140 shown in FIG. 3 is used for storing information in each memory cell 200. In FIG. 11 and FIG. 12, the magnetoresistive film is shown with “140”, which is the same as the reference in FIG. Further, the constituent elements of the magnetoresistive effect film are also denoted by the same reference numerals as those in FIG. 3, and the redundant description of these constituent elements will be omitted below.

  Part (a) of FIG. 11 shows a cross-sectional view of the magnetic memory 20 focusing on one memory cell 200, and part (b) shows an enlarged area around the magnetoresistive film 140 in the memory cell 200. A cross-sectional view is shown. In FIG. 12, an equivalent circuit of the magnetic memory 20 is shown focusing on one memory cell 200.

  In FIG. 11, part (a) shows a three-dimensional orthogonal coordinate axis. Among these, the Y-axis direction is a direction perpendicular to the paper surface, the Y1 direction is toward the back of the paper surface, and the Y2 direction is toward the front of the paper surface. In the following description, for example, simply referring to the X-axis direction indicates that either the X1 direction or the X2 direction may be used, and the same applies to the Y-axis direction and the Z-axis direction.

  The magnetic memory 20 of the present embodiment is configured by arranging a plurality of memory cells 200 in a matrix on the XY plane on the orthogonal coordinate axis.

  Each memory cell 200 is roughly composed of a magnetoresistive film 140 and a MOS field effect transistor (FET) 210.

  Here, in general, the MOS type FET includes a p-channel MOS type FET in which holes are carriers, and an n-channel MOS type FET in which electrons are carriers. The MOS type FET 210 of the present embodiment is an n-channel MOS type. FET. The magnetic memory described for the basic form is not limited to the form using the n-channel MOS type FET, but may be the form using the p-channel MOS type FET.

  The MOS type FET 210 is formed by injecting a p-type impurity into the silicon substrate 211 and injecting an n-type impurity spaced apart from each other in the vicinity of the surface of the p-well region 212. Two impurity diffusion regions 213a and 213b are provided. Here, one impurity diffusion region 213a is a source S, and the other impurity diffusion region 213b is a drain D. In the MOS FET 210, a gate electrode G is provided on the surface of the p-well region 212 between the two impurity diffusion regions 213a and 213b via a gate insulating film 214.

  The source S of the MOS type FET 210 is electrically connected to the base layer 141 of the magnetoresistive effect film 140 through the vertical wiring 201 and the intralayer wiring 202. Further, the plate line 203 is electrically connected to the drain D through the vertical wiring 201. The gate electrode G is electrically connected to the read word line 204. Note that, unlike the present embodiment, the gate electrode G may be configured such that a part of the read word line also serves as the gate electrode.

  In the memory cell 200 of the present embodiment, the bit line 206 is electrically connected to the protective layer 146 of the magnetoresistive film 140. A write word line 205 is provided separately below the magnetoresistive film 140.

  In this memory cell 200, the direction of the easy axis in the free magnetic layer 145 of the magnetoresistive film 140 is set to the X-axis direction shown in part (a) of FIG. Set to direction. Although the method for forming the easy magnetization axis is not specified here, it may be formed by heat treatment or shape anisotropy. In the case where the easy magnetization axis is formed in the X-axis direction due to shape anisotropy, the cross-sectional shape parallel to the film surface of the magnetoresistive effect film 140 (cross-sectional shape parallel to the XY plane) is set to be more than the side in the Y-axis direction. A rectangle with a long side in the X-axis direction.

  In the magnetic memory 20, the surface of the silicon substrate 211 and the gate electrode G in each memory cell 200 are covered with an interlayer insulating film 207 such as a silicon nitride film or a silicon oxide film.

  Further, the magnetoresistive film 140, the plate line 203, the read word line 204, the bit line 206, the write word line 205, the vertical wiring 201, and the intra-layer wiring 202 are other than the electrical connection described above. The interlayer insulating film 207 is electrically insulated from each other.

  In the magnetic memory 20, information corresponding to 1 bit is held in the magnetoresistive film 140 in each memory cell 200. Information is retained depending on whether the magnetization direction of the free magnetic layer 145 is parallel or antiparallel to the magnetization direction of the reference layer 143c.

  Next, a write operation and a read operation for each memory cell 200 will be described.

  First, a write operation for the memory cell 200 will be described.

  The write operation on the memory cell 200 is performed by passing a current through the bit line 206 and the write word line 205 disposed above and below the magnetoresistive film 140.

  In the present embodiment, the combination of the bit line 206 and the write word line 205 corresponds to an example of a write unit in the basic form of the magnetic memory described above.

  The bit line 206 extends in the X-axis direction above the magnetoresistive film 140. When a current flows through the bit line 206, a magnetic field induced around the bit line 206 is applied to the magnetoresistive film 140 in the Y-axis direction. The write word line 205 extends in the Y-axis direction below the magnetoresistive film 140. When a current flows through the write word line 205, a magnetic field induced around the write word line 205 is applied to the magnetoresistive film 140 in the X-axis direction.

  Here, the magnetization of the free magnetization layer 145 of the magnetoresistive film 140 is in the X-axis direction (for example, the direction of X2) when a magnetic field is not substantially applied, and the magnetization direction is stable.

  During a write operation on the memory cell 200, a current flows simultaneously through the bit line 206 and the write word line 205. For example, when the magnetization of the free magnetic layer 145 is directed in the X1 direction, a current in the Y1 direction flows through the write word line 205. Thereby, a magnetic field is applied to the magnetoresistive film 140 in the direction of X1. At this time, a current in one of the X1 direction and the X2 direction flows through the bit line 206. A magnetic field generated by the current passed through the bit line 206 is applied to the magnetoresistive effect film 140 in the Y1 direction or the Y2 direction, and a part of the magnetic field for allowing the magnetization of the free magnetic layer 145 to cross the hard axis barrier. Function as.

  By applying such a magnetic field, the magnetization of the free magnetic layer 145 is simultaneously exposed to the magnetic field in the X1 direction and the Y1 direction or the Y2 direction. As a result, the magnetization of the free magnetic layer 145 that was oriented in the X2 direction before application of the magnetic field is reversed in the X1 direction. Even after the magnetic field is removed, the magnetization of the free magnetic layer 145 is in the X1 direction, and the magnetization is stable unless a magnetic field for the next write operation or a magnetic field for erasure is applied.

  In this way, “1” or “0” can be recorded in the magnetoresistive film 140 according to the magnetization direction of the free magnetic layer 145. For example, when the magnetization direction of the reference layer 143c is the X1 direction and the magnetization direction of the free magnetic layer 145 is the X1 direction (the resistance value is small), “1”, the X2 direction (the resistance value is large) In the state), “0” is represented at the design stage.

  Note that the magnitude of the current supplied to the bit line 206 and the write word line 205 during the write operation is such that even if a current flows only in either the bit line 206 or the write word line 205, the free magnetization It is set to such an extent that the magnetization reversal of the layer 145 does not occur. As a result, only the magnetization of the free magnetization layer 145 of the magnetoresistive film 140 of the memory cell 200 to be written, which corresponds to the intersection of the bit line 206 supplied with the current and the write word line 205 supplied with the current, is recorded. Is done. Further, during the write operation, the source S side is set to high impedance so that the current passed through the bit line 206 does not flow into the magnetoresistive film 140.

  Next, a read operation for the memory cell 200 will be described.

  In the read operation for the memory cell 200, a negative voltage is applied to the source S in the MOS type FET 210 of the memory cell 200 to be read through the bit line 206, and the memory cell is connected through the read word line 204. This is performed by applying a voltage (positive voltage) larger than the threshold voltage of the MOS FET 210 to the gate electrode G of the 200 MOS FET 210.

  By applying such a voltage, only the MOS FET 210 of the memory cell 200 to be read is turned on, and electrons flow from the bit line 206 to the plate line 203 via the magnetoresistive film 140, the source S, and the drain D. .

  Here, in this embodiment, as shown in FIG. 12, a current value detector 25 such as an ammeter is connected to the plate line 203 of the magnetic memory 20. By detecting the current value when the voltage is applied as described above by the current value detector 25, the magnetoresistance value corresponding to the magnetization direction of the free magnetic layer 145 with respect to the magnetization direction of the reference layer 143c is detected. . Thereby, the information “1” or “0” held in the magnetoresistive film 140 of each memory cell 200 of the magnetic memory 20 can be read.

  In the magnetic memory 20 of this embodiment, the reference layer 143c and the free magnetic layer 145 of the magnetoresistive effect film 140 of each memory cell 200 are formed of a film in which Ge or Cu is added as a fifth element to a CoFeAlSi alloy. Therefore, it has excellent reproduction output and sensitivity. Therefore, the magnetic memory 20 accurately detects the difference in magnetoresistive value corresponding to the information “0” and “1” held in the magnetoresistive effect film 140 of each memory cell 200 when reading information. be able to.

  In this embodiment, as an embodiment of the magnetic memory described above with respect to the basic form, the form in which the magnetoresistive effect film 140 shown in FIG. 3 is employed as the magnetoresistive effect film of each memory cell is illustrated. The magnetic memory described above with respect to the form is not limited to this. For example, the form in which the magnetoresistive effect film 150 shown in FIG. 8 or the magnetoresistive effect film 160 shown in FIG. 9 is adopted as the magnetoresistive effect film of each memory cell. Etc.

  In the present embodiment, the memory cell 200 to be read at the time of reading information is selected by turning on the MOS FET 210 of the memory cell 200. However, the magnetic memory described with respect to the basic form is not limited to this form, and various generally known selection methods can be applied as a method for selecting a memory cell to be read.

  In the magnetic memory 20 of the present embodiment described above, the method and examples of forming the magnetoresistive film 140 of each memory cell 200 are described in the magnetoresistive film 140 of FIG. 3 of the first embodiment described above. Since it overlaps with the description of the forming method and the embodiment, it is omitted.

  Next, a fifth embodiment will be described. The fifth embodiment is also a specific embodiment of the magnetoresistive effect element and magnetic memory described in the basic form.

  FIG. 13 is a diagram illustrating a magnetic memory according to the fifth embodiment.

  The magnetic memory 30 of the present embodiment is configured by arranging a plurality of memory cells 300 each storing information corresponding to 1 bit in a matrix. Also in the magnetic memory 30 of the present embodiment, a magnetoresistive film equivalent to the magnetoresistive film 140 shown in FIG. 3 is used for storing information in each memory cell 300, as in the fourth embodiment described above. It has been broken. Therefore, in FIG. 13, this magnetoresistive film is shown with “140”, which is the same reference numeral as in FIG.

  The magnetic memory 30 shown in FIG. 13 is different from the magnetic memory 20 of the fourth embodiment in the mechanism for writing information to the magnetoresistive film 140.

  Each memory cell 300 of the magnetic memory 30 has the same configuration as the memory cell 200 shown in FIG. 11 except that the write word line 205 is not provided. Hereinafter, FIG. 11 will be described with reference to FIG.

  The magnetic memory 30 of the present embodiment is different from the magnetic memory 20 of the fourth embodiment in the write operation for each memory cell 300.

  Unlike the magnetic memory 20 of the fourth embodiment, the write operation in the magnetic memory 30 of the present embodiment is performed using the bit line 301 and the MOS type FET 210.

  In the present embodiment, the combination of the bit line 301 and the MOS FET 210 corresponds to an example of a writing unit in the basic form of the magnetic memory described above.

  In this write operation, a polarized spin current Iw described below is passed through the magnetoresistive film 140 of the memory cell 300 to be written via the bit line 301. At this time, the memory cell 300 to be written is selected by turning on the MOS FET 210 of the memory cell 300 and opening the flow path of the polarized spin current Iw from the bit line 301 to the plate line 203. Is done.

  The polarized spin current Iw is an electron flow consisting only of electrons having spins in one of two possible spin directions. When this polarized spin current Iw is applied to the magnetoresistive effect film 140 in the direction of Z1 or Z2 in the figure, torque is generated in the magnetization of the free magnetic layer 145, so-called spin injection magnetization reversal. Happens. In the spin injection magnetization reversal at this time, the magnetization of the free magnetic layer 145 changes with respect to the magnetization direction of the reference layer 143c according to the flow direction of the polarized spin current Iw flowing in the stacking direction of the magnetoresistive effect film 140. The direction is parallel or antiparallel.

  In the write operation in the magnetic memory 30 of FIG. 13, the information is written to the GMR element 140 of each memory cell 300 by setting the direction of the flow of the polarized spin current Iw according to the information to be written. Will be. At this time, the spin direction of the electrons forming the polarized spin current Iw only needs to be aligned in one of the two possible directions of the electrons, and it does not matter which direction they are aligned. To do.

  Here, the amount of the polarized spin current Iw is smaller than the amount of current flowing through the bit line 206 and the write word line 205 during the write operation of the magnetic memory 20 of the fourth embodiment of FIG. Can be reduced.

  The read operation for each memory cell 300 of the magnetic memory 30 of the present embodiment is the same as the read operation for each memory cell 200 of the magnetic memory 20 of the fourth embodiment shown in FIG.

  Further, in the magnetic memory 30 of the present embodiment, the method for forming the magnetoresistive effect film 140 of each memory cell 300 and the explanation of the examples are described in the method for forming the magnetoresistive effect film 140 of FIG. Since it overlaps with the description of the embodiment, it will be omitted.

  The magnetic memory 30 of the present embodiment described above has the same effect as the magnetic memory 20 of the fourth embodiment described above. Furthermore, the magnetic memory 30 of this embodiment can reduce power consumption compared with the magnetic memory 20 of 4th Embodiment.

  In this embodiment, the memory cell 300 to be written at the time of writing information is selected by turning on the MOS FET 210 of the memory cell 300. However, the magnetic memory described with respect to the basic mode is not limited to this mode, and various generally known selection methods can be applied as a method of selecting a memory cell to be written.

  In the above description, a hard disk device provided with a magnetic disk is illustrated as an embodiment of the information storage device described with respect to the basic form. However, the information storage device described with respect to the basic form is not limited to this. A magnetic tape device or the like that performs information recording and information reproduction on a tape may also be used.

  In the above, as an embodiment of the magnetic head described with respect to the basic form, a magnetic head provided with one magnetoresistive element as a reproducing element and one inductive recording element as a recording element is illustrated. The magnetic head described with respect to the basic form is not limited to this. For example, the magnetic head may include only a magnetoresistive element as a reproducing element, or may include a plurality of magnetoresistive elements as reproducing elements. It may be.

It is a figure which shows the hard disk apparatus equivalent to one specific embodiment of the information storage device demonstrated about the basic form. It is a figure which shows the detail of the magnetic head of FIG. 1 which is one specific embodiment of the magnetic head demonstrated about the basic form. It is sectional drawing of the magnetoresistive effect film | membrane shown in FIG. It is a graph showing the relationship between the composition of Ge and specific resistance when (Co ₅₀ Fe ₂₅ Al _12.5 Si _12.5 ) _(100-X) Ge _X is formed on a SiO ₂ substrate. It is a figure which shows a magnetoresistive curve. It is a graph which shows magnetoresistive value change rate MR ratio about the 1st and 2nd example. It is a graph which shows Hin about the 1st and 2nd Example. It is a graph which shows Hc about the 1st and 2nd example. It is sectional drawing of the magnetoresistive effect film | membrane of 2nd Embodiment. It is sectional drawing of the magnetoresistive effect film of 3rd Embodiment. It is a figure which shows the magnetic memory of 4th Embodiment. It is a figure which shows the equivalent circuit of the magnetic memory shown in FIG. It is a figure which shows the magnetic memory of 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Hard disk apparatus 11 Housing 12 Hub 13 Magnetic disk 14 Actuator unit 15 Arm 16 Suspension 17 Control circuit 20, 30 Magnetic memory 25 Current value detector 100 Magnetic head 101 Base body 102 Alumina film 120 Magnetoresistive element 121 Lower electrode 122 Upper electrode 123 Insulating film 124 Magnetic domain control film 125 Alumina film 130 Inductive recording element 131 Upper magnetic pole 132 Recording gap layer 133 Lower magnetic pole 140, 150, 160 Magnetoresistive film 141 Underlayer 142, 154 Antiferromagnetic layer 142 ′ Lower antiferromagnetic layer 143, 153 Fixed magnetization stack 143 ′ Lower fixed magnetization stack 143a, 153a Pinned layer 143a ′ Lower pinned layer 143b, 153b Nonmagnetic coupling layer 143b ′ Lower nonmagnetic coupling layer 143c, 153c Reference layer 143c ′ Lower reference layer 144, 152 Nonmagnetic layer 144 ′ Lower nonmagnetic layer 145, 151 Free magnetic layer 146 Protective layer 162 Upper antiferromagnetic layer 163 Upper fixed magnetization stack 163a Upper pinned layer 163b Upper nonmagnetic coupling Layer 163c Upper reference layer 164 Upper nonmagnetic layer 200,300 Memory cell 201 Vertical wiring 202 In-layer wiring 203 Plate line 204 Read word line 205 Write word line 206, 301 Bit line 207 Interlayer insulating film 210 MOS type FET
211 Silicon substrate 212 P well region 213a, 213b Impurity diffusion region 214 Gate insulating film

Claims (9)

In a CPP (Current-Perpendicular-to-Plane) type magnetoresistive effect element having upper and lower electrode terminals for passing a sense current in a direction perpendicular to the film surface of the laminated film constituting the element,
A reference layer in which the direction of magnetization including Ge and / or Cu is fixed to the CoFeAlSi alloy;
A free magnetic layer in which the direction of magnetization including Ge and / or Cu in the CoFeAlSi alloy changes to a direction according to an external action;
A magnetoresistive effect element comprising a nonmagnetic layer formed of a nonmagnetic material between the reference layer and the free magnetic layer. The direction of magnetization formed of a magnetic material on the opposite side of the reference layer to the non-magnetic layer side is fixed in a second direction opposite to the first direction in which the magnetization of the reference layer is to be fixed The pinned layer,
An antiferromagnetic coupling between the magnetization of the pinned layer and the magnetization of the reference layer, which is formed between the pinned layer and the reference layer, causes the magnetization in the reference layer to be in the first direction. The magnetoresistive effect element according to claim 1, further comprising a laminated ferrimagnetic structure including a nonmagnetic coupling layer made of a nonmagnetic material and fixed to the substrate.   An antiferromagnetic layer formed of an antiferromagnetic material on the opposite side of the pinned layer to the nonmagnetic coupling layer side and fixing the magnetization direction in the pinned layer in the second direction; 3. The magnetoresistive element according to claim 2, wherein A second nonmagnetic layer formed of a nonmagnetic material on the opposite side of the free magnetic layer to the nonmagnetic layer side;
A second reference layer formed on a side opposite to the free magnetic layer side of the second nonmagnetic layer and having a magnetization direction fixed to the same direction as the magnetization direction in the reference layer. The magnetoresistive effect element according to claim 1, wherein the magnetoresistive effect element is provided. The direction of magnetization formed of a magnetic material on the side opposite to the second nonmagnetic layer side of the second reference layer is the first direction in which the magnetization in the second reference layer is to be fixed A second pinned layer fixed in a second direction opposite to
Antiferromagnetically coupling the magnetization in the second pinned layer and the magnetization in the second reference layer formed between the second pinned layer and the second reference layer; 5. A magnetoresistive effect element according to claim 4, further comprising: a second nonmagnetic coupling layer made of a nonmagnetic material that fixes the magnetization in the second reference layer in the first direction. .   The magnetization direction in the second pinned layer formed of an antiferromagnetic material on the opposite side of the second pinned layer to the second nonmagnetic coupling layer side is fixed to the second direction. 6. The magnetoresistive element according to claim 5, further comprising a second antiferromagnetic layer. In a CPP (Current-Perpendicular-to-Plane) type magnetic head having upper and lower electrode terminals for passing a sense current in a direction perpendicular to a film surface of a laminated film constituting an element,
A reference layer in which the direction of magnetization including Ge and / or Cu is fixed to the CoFeAlSi alloy;
A free magnetic layer in which the direction of magnetization including Ge and / or Cu in the CoFeAlSi alloy changes to a direction according to an external action;
A nonmagnetic layer formed of a nonmagnetic material between the reference layer and the free magnetic layer;
A magnetic head comprising a pair of electrodes for flowing current in the stacking direction. A magnetic storage medium, and
In a CPP (Current-Perpendicular-to-Plane) type magnetic head having upper and lower electrode terminals for passing a sense current in a direction perpendicular to a film surface of a laminated film constituting an element,
A reference layer in which the direction of magnetization including Ge and / or Cu as the fifth element is fixed to the CoFeAlSi alloy;
A free magnetization layer in which the direction of magnetization including Ge and / or Cu as a fifth element in a CoFeAlSi alloy changes to a direction according to an external action;
A nonmagnetic layer formed of a nonmagnetic material between the reference layer and the free magnetic layer;
An information storage device comprising: a magnetic head including a pair of electrodes for flowing current in the stacking direction.   7. The magnetoresistive effect element according to claim 1, wherein the direction of magnetization in the free magnetic layer is directed to the direction according to information by applying an action according to information to the free magnetic layer. A magnetic memory comprising a writing unit for writing the magnetization direction in the magnetic memory.

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