JP2004192744A - Magnetic head and magnetic recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic cell in which a reverse current when magnetization is reversed by direct driving by a current can be reduced, and further provide a magnetic memory cell using it. <P>SOLUTION: This cell is a magnetic cell provided with a first ferromagnetic layer C1 of which the magnetization (M1) direction is fixed substantially a first direction, a second ferromagnetic layer C2 of which the magnetization (M2) direction is fixed substantially a second direction being opposite to the first direction, a third ferromagnetic layer A which is provided between the first and the second ferromagnetic layers and of which the magnetization direction is variable, a first intermediate layer B1 provided between the first and the third ferromagnetic layers, and a second intermediate layer B2 provided between the second and the third ferromagnetic layers. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a magnetic head, and more particularly, to a magnetic head that can be used in a magnetic disk device or the like and that can perform high-density recording.
[0002]
[Prior art]
In recent years, the magnetic recording density of hard disk drives has rapidly increased, and the required recording frequency has also increased to several hundred MHz.
[0003]
With respect to the reproducing head, with the advent of a GMR (Giant Magnet-Resistance) head using spin-dependent scattering as an operation principle, the output has been drastically increased to cope with high recording density. Also, many structures have been proposed to cope with higher recording density. In order to meet the purpose, there has been proposed a reproducing element of a type in which a current is supplied perpendicularly to a multilayer film laminated surface. For example, a TMR (Tunneling-junction Magnet-Resistance) head, a CPPGMR (Current Perpendicular to the Plane GMR) head, and the like correspond to those reproducing elements.
[0004]
In this element design, the magnetization orthogonal arrangement of the pinned layer and the free layer that responds to the external magnetic field, the soft magnetic design of the free layer, and the interface scattering and bulk scattering to further increase the output are remarkable. The design to do so is important. The output of the CPPGMR structure in which the upper and lower portions of the free layer are sandwiched by the pinned layer is expected because interface scattering occurs between the upper and lower portions of the free layer. For this purpose, the magnetization of the pin layers sandwiched between the upper and lower layers needs to be orthogonal to the free layer, and the upper and lower pin layers must be oriented in the same direction. Further, in order to respond sensitively to an external magnetic field, it is desirable to lower the saturation magnetization.
[0005]
Further, in the case of a general shield type head, it is necessary that the both sides thereof are sandwiched by the shield, the total film thickness of the element is contained in the shield, and the free layer is located substantially in the middle of the shield. The optical patterning process in the track width direction compared to the recording head has advantages such as easier microfine photolithography as compared to the case where the depth of focus is reduced because the structure is relatively simple.
[0006]
On the other hand, in a recording head, a principle is used in which an alternating current is applied to a coil formed through a thin film process to excite a recording magnetic material interlinked with the coil to record signal information.
[0007]
A technique for causing magnetization reversal by passing a current through a magnetic body is disclosed in, for example, Non-Patent Document 1. However, this is not for the magnetic head.
[0008]
[Non-patent document 1]
FJ Albert, et al., Appl.Phy. Lett. 77, 3809 (2000)
[0009]
[Problems to be solved by the invention]
In a recording head, it is becoming difficult to increase the recording density. That is, in the case of the conventional method using a coil, the magnetization response of the recording material to an external magnetic field is limited by the inductance of the coil and the magnetic circuit, and it is difficult in principle to cope with a higher frequency. In order to cope with high frequencies, it is necessary to reduce the inductance of the magnetic circuit, and the entire magnetic circuit must be formed small. The track width needs to be machined over high steps, up to about 10 microns due to the presence of the coil. For this reason, many intermediate processes are required due to the depth of focus of photolithography, and the yield of the track width defining step is reduced, resulting in an increase in cost.
[0010]
As described above, conventionally, the recording head uses the principle that a recording signal is applied to a coil by an electric current and the excited signal magnetic field is transmitted to a magnetic material to perform recording. To increase the recording density, the size is reduced by reducing the size. It has responded, but now it appears to hit the wall due to its principle and structure.
[0011]
The present invention has been made based on the recognition of such a problem, and it is an object of the present invention to provide a magnetic head capable of generating a write magnetic field by a fundamentally different principle from the conventional coil system and capable of dramatically increasing high-density recording. .
[0012]
[Means for Solving the Problems]
The present invention provides a magnetic head capable of performing higher-density magnetic recording than in the past by using a technique of controlling the magnetization by passing a spin-polarized current to a magnetic material. The magnetization of the magnetic pole of the magnetic head is reversed by injecting the spin-polarized electrons into the recording magnetic pole. By doing so, high-frequency recording becomes possible, and furthermore, a recording coil becomes unnecessary, so that track narrowing becomes easy. In addition, there is a cost advantage by reducing the number of processes.
[0013]
That is, the first magnetic head of the present invention includes a first ferromagnetic layer whose magnetization is substantially fixed in a first direction, a second ferromagnetic layer whose magnetization direction is variable, A first intermediate layer provided between the first ferromagnetic layer and the second ferromagnetic layer,
A current is caused to flow between the first and second ferromagnetic layers to cause spin-polarized electrons to act on the second ferromagnetic layer, thereby changing the direction of magnetization of the second ferromagnetic layer to the current. Determine the direction according to the direction of
Information can be magnetically recorded on a magnetic recording medium by a recording magnetic field generated by the determined magnetization of the second ferromagnetic layer.
[0014]
According to the above configuration, it is possible to provide a magnetic head capable of generating a write magnetic field by a fundamentally different principle from the conventional coil system and capable of achieving a remarkable high-density recording.
[0015]
Further, the second magnetic head of the present invention includes a first ferromagnetic layer whose magnetization is substantially fixed in a first direction, a second ferromagnetic layer whose magnetization direction is variable, A first intermediate layer provided between the first ferromagnetic layer and the second ferromagnetic layer,
A current is caused to flow between the first and second ferromagnetic layers to cause spin-polarized electrons to act on the second ferromagnetic layer, thereby changing the direction of magnetization of the second ferromagnetic layer to the current. Determine the direction according to the direction of
The information is recordable by determining the magnetization of the magnetic recording medium by flowing the spin-polarized electrons from the second ferromagnetic layer to the magnetic recording medium.
[0016]
According to the above configuration, it is also possible to provide a magnetic head capable of generating a writing magnetic field by a principle fundamentally different from that of the conventional coil system and capable of dramatically increasing high-density recording.
[0017]
In these first and second magnetic heads, when an electron current flows from the first ferromagnetic layer to the second ferromagnetic layer, the magnetization of the second ferromagnetic layer is reduced. The direction is the first direction, and when an electron current flows from the second ferromagnetic layer to the first ferromagnetic layer, the direction of the magnetization of the second ferromagnetic layer is May be opposite to the first direction.
[0018]
The third magnetic head according to the present invention may further include a first ferromagnetic layer whose magnetization is substantially fixed in the first direction, and a magnetization in a second direction opposite to the first direction. A substantially fixed third ferromagnetic layer, and a second ferromagnetic layer provided between the first and third ferromagnetic layers and having a variable magnetization direction. Body layer, a first intermediate layer provided between the first ferromagnetic layer and the second ferromagnetic layer, the second ferromagnetic layer and the third ferromagnetic layer. A second intermediate layer provided between the body layer and the body layer,
A current is caused to flow between the first and third ferromagnetic layers to cause spin-polarized electrons to act on the second ferromagnetic layer to change the direction of magnetization of the second ferromagnetic layer. Determine the direction according to the direction,
Information can be magnetically recorded on a magnetic recording medium by a recording magnetic field generated by the determined magnetization of the second ferromagnetic layer.
[0019]
According to the above configuration, it is also possible to provide a magnetic head capable of generating a writing magnetic field by a principle fundamentally different from that of the conventional coil system and capable of dramatically increasing high-density recording.
[0020]
The fourth magnetic head according to the present invention may further include a first ferromagnetic layer whose magnetization is substantially fixed in the first direction, and a second ferromagnetic layer whose magnetization is in a second direction opposite to the first direction. A substantially fixed third ferromagnetic layer, and a second ferromagnetic layer provided between the first and third ferromagnetic layers and having a variable magnetization direction. Body layer, a first intermediate layer provided between the first ferromagnetic layer and the second ferromagnetic layer, the second ferromagnetic layer and the third ferromagnetic layer. A second intermediate layer provided between the body layer and the body layer,
A current is caused to flow between the first and third ferromagnetic layers to cause spin-polarized electrons to act on the second ferromagnetic layer to change the direction of magnetization of the second ferromagnetic layer. Determine the direction according to the direction,
The information is recordable by determining the magnetization of the magnetic recording medium by flowing the spin-polarized electrons from the second ferromagnetic layer to the magnetic recording medium.
[0021]
According to the above configuration, it is also possible to provide a magnetic head capable of generating a writing magnetic field by a principle fundamentally different from that of the conventional coil system and capable of dramatically increasing high-density recording. In the third and fourth magnetic heads, when an electron current flows from the first ferromagnetic layer to the third ferromagnetic layer via the second ferromagnetic layer, The direction of the magnetization of the second ferromagnetic layer is the first direction;
When an electron current is passed from the third ferromagnetic layer to the first ferromagnetic layer via the second ferromagnetic layer, the electron current of the second ferromagnetic layer The direction of the magnetization may be the second direction.
[0022]
In any of the above magnetic heads, the magnetization of the second ferromagnetic layer is oriented in a direction substantially perpendicular to the first direction when the current is not flowing. Can be.
[0023]
On the other hand, a fifth magnetic head according to the present invention includes a first ferromagnetic layer whose magnetization is substantially fixed in a first direction, a second ferromagnetic layer whose magnetization direction is variable, A first intermediate layer provided between the first ferromagnetic layer and the second ferromagnetic layer,
Allowing an electron current to flow from the magnetic recording medium into the second ferromagnetic layer so that the magnetization of the second ferromagnetic layer has a direction corresponding to a spin-polarized state of the electron current;
The distance between the first and second ferromagnetic layers determined according to a relative relationship between the direction of the magnetization of the first ferromagnetic material and the direction of the magnetization of the second ferromagnetic material. The information recorded on the magnetic recording medium can be read by detecting a change in resistance.
[0024]
According to the above configuration, it is possible to provide a reading magnetic head capable of generating a writing magnetic field based on a fundamentally different principle from the conventional coil system and capable of dramatically increasing high-density recording.
In the fifth magnetic head, the first intermediate layer is made of an insulator having minute holes, and the first and second ferromagnetic layers are connected to each other through the minute holes. can do.
[0025]
In any of the above magnetic heads, the first ferromagnetic layer may have a magnetization direction fixed by an adjacent antiferromagnetic layer.
[0026]
In addition, at least one of the first and third ferromagnetic layers may have a magnetization direction fixed by an adjacent antiferromagnetic layer.
[0027]
On the other hand, a magnetic recording apparatus of the present invention includes any one of the magnetic heads described above, and is capable of magnetically recording information on a magnetic recording medium.
[0028]
Alternatively, a magnetic recording apparatus according to the present invention includes the fifth magnetic head, and is capable of reproducing information magnetically recorded on a magnetic recording medium.
[0029]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0030]
FIG. 1 is a schematic view illustrating a basic cross-sectional structure of a main part of a magnetic head for recording according to an embodiment of the present invention. This magnetic head includes a magnetization fixed layer C made of a magnetic material whose magnetization is substantially fixed in one direction, an intermediate layer B made of a nonmagnetic material, and a soft magnetic material magnetically softer than the magnetization fixed layer C. And a layer A. That is, the magnetization 1 of the pinned layer is fixed in one direction, and the magnetization M of the soft magnetic layer A is reversible.
[0031]
The magnetization fixed layer C can be formed of, for example, a magnetic material that is magnetically harder (harder) than the soft magnetic material layer A. When the material of the magnetization fixed layer C is not a magnetic material harder than the soft magnetic material layer A, the magnetization M1 is fixed in a predetermined direction by an antiferromagnetic material (not shown) or the like. May be done. This point will be described later in detail with reference to examples.
[0032]
A current I flows in the magnetization fixed layer C, the intermediate layer B, and the soft magnetic layer A in any direction indicated by an arrow in FIG. Then, the magnetization M of the soft magnetic layer A is directed in a predetermined direction by the current I, and a recording magnetic field is applied to the recording medium R by the magnetization M, whereby predetermined information can be magnetically recorded. That is, the magnetization of the soft magnetic layer A is reversed by the spin polarization current. The soft magnetic layer A acts as a “write magnetic pole” or a “recording magnetic pole” of the magnetic head.
[0033]
FIG. 2 is a schematic diagram illustrating the mechanism of magnetization reversal in the magnetic head of this example.
[0034]
That is, first, as shown in FIG. 2A, when an electron current I flows from the magnetization fixed layer C to the soft magnetic layer A, the magnetization M of the soft magnetic layer A is changed to the magnetization of the magnetization fixed layer C. It can be reversed in the same direction as M1. That is, when the electron current I flows in this direction, the electron spin is first polarized in the magnetization fixed layer C according to the direction of the magnetization M1. That is, the magnetization fixed layer C functions as a “spin-polarized electron emitter”. Then, the spin-polarized electrons flow into the soft magnetic layer A, and the magnetization M is reversed in the same direction as the magnetization M1 of the magnetization fixed layer C.
[0035]
On the other hand, as shown in FIG. 2B, when an electron current I flows from the soft magnetic layer A to the magnetization fixed layer C, writing can be performed in the opposite direction. In other words, the spin electrons corresponding to the magnetization M1 of the magnetization fixed layer C can easily pass through the magnetization fixed layer C, while the spin electrons in the opposite direction to the magnetization M1 generate It is reflected at the interface with a high probability. Then, the spin-polarized electrons reflected in this way return to the soft magnetic layer A, thereby reversing the magnetization M of the soft magnetic layer A in a direction opposite to the magnetization M1 of the magnetization fixed layer C.
[0036]
As described above, the magnetic recording can be performed by directing the magnetization M of the soft magnetic layer A in a predetermined direction in accordance with the direction of the current and applying the magnetization M to the recording medium R.
[0037]
Further, as will be described later in detail with reference to Examples, in the present invention, information is recorded on the recording medium R by flowing a spin-polarized current from the soft magnetic layer A to the recording medium R. Is also possible.
[0038]
As described above, in the present invention, the magnetization M of the soft magnetic layer A can be reversed in a predetermined direction by the current direct drive type magnetization reversal mechanism using the spin-polarized current. For this reason, a much faster magnetization reversal becomes possible as compared with a conventional magnetic head using a leakage current magnetic field from a coil. As a result, a high operating frequency required for ultra-high-density magnetic recording can be realized. Furthermore, the size can be significantly reduced as compared with the case where the coil is used, and the track width and the recording bit size can be easily reduced.
[0039]
FIG. 3 is a schematic view illustrating a basic cross-sectional structure of a main part of a magnetic head according to another embodiment of the present invention. This magnetic head is also a recording head, and includes a magnetization fixed layer C1 made of a hard magnetic material, an intermediate layer B1 made of a nonmagnetic material, a soft magnetic material layer A magnetically softer than the magnetization fixed layer C, It has a structure in which an intermediate layer B2 made of a nonmagnetic material and a magnetization fixed layer C2 made of a hard magnetic material are stacked in this order. The magnetization fixed layers C1 and C2 have their magnetizations M1 and M2 substantially fixed in directions antiparallel to each other. The magnetization M of the soft magnetic layer A is variable.
[0040]
Also in the magnetic head of this specific example, the direction of the magnetization M of the soft magnetic layer A can be controlled by passing the current I between the magnetization fixed layers C1 and C2 at both ends. In this manner, information can be magnetically written on the recording medium R by a recording magnetic field corresponding to the magnetization M of the soft magnetic layer A.
[0041]
FIG. 4 is a schematic cross-sectional view for explaining the mechanism of “magnetization reversal” in the magnetic head shown in FIG. The mechanism for providing the two magnetization fixed layers C1 and C2 and passing the current I across the interface to reverse the magnetization M of the soft magnetic layer A is as follows.
[0042]
First, in FIG. 4A, electrons that have passed through the first magnetization pinned layer C1 having the magnetization M1 have a spin in the direction of the magnetization M1. Is transmitted to the soft magnetic layer A, and acts on the magnetization M. On the other hand, the magnetization M2 of the second magnetization fixed layer C2 is opposite to the magnetization M1. Therefore, at the interface where the flow of electrons enters the second magnetization fixed layer C2, the electrons having the spin (upward in the figure) in the same direction as the magnetization M1 are reflected and come into contact with the second magnetization fixed layer C2. It accumulates in the middle layer B2. This reverse spin also acts on the soft magnetic layer A. That is, since the spin electrons that have passed through the first magnetization pinned layer C1 act twice on the soft magnetic layer A, the writing action is substantially doubled. As a result, writing to the soft magnetic layer A can be performed with a smaller current than the magnetic head shown in FIG.
[0043]
FIG. 4B shows a case where the current I is inverted. In this case, the electrons constituting the current I first have a spin in this direction (downward in the drawing) under the action of the magnetization M2 of the second magnetization fixed layer C2. The spin electrons act on the magnetization M in the soft magnetic layer A. Furthermore, the spin electrons are reflected at the interface with the first magnetization pinned layer C1 having the magnetization M1 in the opposite direction to the spin electrons, accumulate in the intermediate layer B2, and act again on the magnetization M of the soft magnetic layer A.
[0044]
As described above, according to the present embodiment, since the magnetizations M1 and M2 of the two magnetization fixed layers are made antiparallel, the spin directions acting on the soft magnetic layer A eventually become the same direction, which is twice as large. Works. As a result, the current for reversing the magnetization of the soft magnetic layer A can be reduced.
[0045]
Next, a reproducing magnetic head according to an embodiment of the present invention will be described.
[0046]
FIG. 5 is a schematic sectional view showing a reproducing magnetic head according to the embodiment of the present invention. That is, in the case of the reproducing magnetic head, the insulating layer IL is provided between the magnetization fixed layer C and the soft magnetic layer A, and the magnetization fixed layer C and the soft magnetic layer A are formed by the minute holes NH formed in the insulating layer IL. It is in contact with the magnetic layer A. Although only one micro hole NH is shown in FIG. 5, the present invention is not limited to this, and a plurality of micro holes NH may be provided. The magnetization fixed layer C can be formed of, for example, a hard magnetic material.
[0047]
As described above, when the magnetization fixed layer C and the soft magnetic layer A are connected via the minute holes NH, a so-called “magnetic point contact” is formed, and an extremely large magnetoresistance effect is obtained. Therefore, the direction of the magnetization M of the soft magnetic layer A can be easily determined by detecting the magnetoresistance effect between the magnetic layers on both sides through the minute holes NH.
[0048]
That is, the conductance when a current flows from the soft magnetic layer A of the magnetic head to the electrode EL1 depends on the relative direction between the magnetization M of the soft magnetic layer A and the magnetization M1 with the magnetization fixed layer C. . In the case of the specific example shown in FIG. 5, if the magnetization M of the soft magnetic layer A is directed toward the ABS, it becomes parallel to the direction of the magnetization M1 of the fixed magnetization layer C. In this case, no domain wall exists at the interface between the magnetization fixed layer C and the soft magnetic layer A in the minute hole NH.
[0049]
On the other hand, if the magnetization M of the soft magnetic layer A is in the opposite direction to the magnetization M1 of the pinned layer C, a domain wall exists at the interface between the soft magnetic layer A and the pinned layer C in the minute hole NH. I do. In this case, a steep domain wall exists because the contact portion between the soft magnetic layer A and the magnetization fixed layer C is narrowed by the minute holes NH. Therefore, the conductance between the soft magnetic layer A and the electrode EL1 is Cp> Cap, where Cp is the case where the magnetization is parallel and Cap is the case where the magnetization is antiparallel.
[0050]
The magnetization M of the soft magnetic layer A is rotated in that direction by receiving a signal magnetic field recorded on the recording layer RL of the medium. The direction of the magnetization M can be detected from the change in conductance through the minute hole NH as described above.
[0051]
On the other hand, the soft magnetic layer A can also receive spin-polarized electrons from the recording layer RL of the medium and change the direction of its magnetization M. That is, when the magnetic head is caused to travel in contact with the medium R, the medium R is electrically grounded, and an electric circuit in which the potential of the electrode EL1 of the magnetic head is higher than the ground (ground potential) is formed. Electrons flow from R into the soft magnetic layer A. That is, spin-polarized electrons corresponding to the recording magnetization of the recording layer RL flow into the soft magnetic layer A. Then, the direction of the magnetization M of the soft magnetic layer A is controlled by the spin-polarized electrons. As a result, when the recording magnetization of the recording layer RL is in the same direction as the magnetization fixed layer C, the conductance is Cp (small resistance), and when the recording magnetization is in the opposite direction, the conductance is Cap (large resistance).
[0052]
Here, there are two forces that change the direction of the magnetization M of the soft magnetic layer A, namely, torque due to spin-polarized electrons flowing from the recording layer RL and torque due to the signal magnetic field recorded in the recording layer RL. . Regarding the signal magnetic field, there is a possibility that noise (so-called “side reading” or “cross talk”) due to a leak signal from a bit other than the recording bit may enter.
[0053]
On the other hand, in the case of reading using spin-polarized electrons, the coercive force Hc of the soft magnetic layer A is appropriately increased to prevent side reading of the signal magnetic field and to record only the recording bits that are in electrical contact. The signal can be read. As described above, if the magnetization M of the soft magnetic layer A is rotated by the torque generated by the spin-polarized electrons, it is easy to read the signal magnetic field of only the recording bit that is in contact, and the magnetic flux is detected. Compared with a signal reproducing method, the method is more resistant to external disturbances, has better resolution, and does not require a shield in the track width direction or the track length direction.
[0054]
Here, it is desirable that the opening diameter of the minute hole NH is approximately 20 nm or less. In addition, the opening shape of the minute hole NH can take various shapes such as a conical shape, a cylindrical shape, a spherical shape, a polygonal pyramid shape, and a polygonal column shape. Further, the number of the minute holes NH may be one or plural.
[0055]
Next, each element constituting the recording or reproducing magnetic head of the present invention will be described in detail.
[0056]
First, iron (Fe), cobalt (Co), nickel (Ni), or iron (Fe), cobalt (Co), and nickel (Ni) are used as materials for the magnetization fixed layers C, C1, and C2 and the soft magnetic layer A. (Ni), an alloy containing at least one element selected from the group consisting of manganese (Mn) and chromium (Cr), a NiFe alloy called "Permalloy", a CoNbZr alloy, a FeTaC alloy, a CoTaZr alloy , FeAlSi-based alloys, soft magnetic materials such as FeB-based alloys, CoFeB-based alloys, Heusler alloys, magnetic semiconductors, CrO ₂ , Fe ₃ O ₄ , La _1-X Sr _X MnO ₃ Any of the half metal magnetic oxides (or half metal magnetic nitrides) can be used.
[0057]
Here, the “magnetic semiconductor” includes at least one of iron (Fe), cobalt (Co), nickel (Ni), chromium (Cr), and manganese (Mn), and a compound semiconductor or an oxide semiconductor. For example, (Ga, Cr) N, (Ga, Mn) N, MnAs, CrAs, (Ga, Cr) As, ZnO: Fe, (Mg, Fe) O And the like.
[0058]
In the present invention, the material of the magnetization fixed layers C, C1, C2, and the soft magnetic layer A may be appropriately selected from those having magnetic characteristics according to the intended use.
[0059]
Further, as a material used for these magnetic layers, a continuous magnetic material may be used, or a composite structure in which fine particles made of a magnetic material are deposited or formed in a non-magnetic matrix may be used. As such a composite structure, for example, a structure called “granular magnetic material” can be given.
[0060]
Further, as a material of the soft magnetic layer A, a two-layer structure of [(Co or CoFe alloy) / (NiFe or NiFeCo or Ni)] or [(Co or CoFe alloy) / (NiFe or A permalloy alloy of NiFeCo or a laminate having a three-layer structure of Ni) / (Co or CoFe alloy) can also be used.
[0061]
On the other hand, the materials of the intermediate layers B, B1, and B2 include copper (Cu), gold (Au), silver (Ag), ruthenium (Ru), and alloys containing at least one of these, and aluminum (Al). ), An oxide or a nitride containing at least one element selected from the group consisting of titanium (Ti), tantalum (Ta), cobalt (Co), nickel (Ni), silicon (Si) and iron (Fe). And an insulator made of fluoride. Further, a different element such as oxygen may be added to these intermediate layers. Furthermore, in the case of an insulating layer, a pinhole may be formed, into which the magnetic layer may enter.
[0062]
On the other hand, in the present invention, the magnetizations of the magnetization fixed layers C, C1, and C2 can be fixed by an antiferromagnetic material. The material of the antiferromagnetic material that can be used in this case is iron manganese (FeMn), platinum manganese (PtMn), palladium manganese (PdMn), palladium platinum manganese (PdPtMn), iridium manganese (IrMn), platinum iridium It is desirable to use manganese (PtIrMn) or the like. In addition, as the intermediate layer when fixing using interlayer bonding, copper (Cu), gold (Au), silver (Ag), ruthenium (Ru), or an alloy containing at least one of these is preferable.
[0063]
Hereinafter, embodiments of the present invention will be described in more detail with reference to examples.
[0064]
(First embodiment)
FIG. 6 is a sectional view showing a main part of a recording magnetic head according to the first embodiment of the present invention.
That is, the magnetic head of this embodiment has a structure in which the electrode EL1, the intermediate layer B1, the soft magnetic layer A, the intermediate layer B2, the hard magnetic layer C, the electrode EL2, and the return yoke RY are stacked in this order. On the back side of the surface facing the recording medium R, a back yoke BY is provided via an insulating layer IL.
[0065]
The mechanism of the reversal of the magnetization M of the soft magnetic layer A in the present embodiment is as described above with reference to FIG. That is, by passing a recording signal current RS in a predetermined direction between the electrode EL1 and the return yoke RY, the magnetization M of the soft magnetic layer A is appropriately reversed, and information can be written on the recording medium R by the magnetic field. it can.
[0066]
As the recording medium R, for example, as shown in the figure, a recording medium in which a magnetic recording layer RL is provided on a backing layer BL made of a soft magnetic substance can be used. In this case, the “write magnetic pole” of the magnetic head, that is, the recording magnetic field emitted from the soft magnetic layer A flows from the backing layer BL to the soft magnetic layer A via the return yoke RY and the back yoke BY, and returns to the closed magnetic circuit. Is advantageous in that it can be formed. Hereinafter, the configuration of the magnetic head of the present embodiment will be described in more detail with reference to the manufacturing steps.
[0067]
The return yoke RY of the magnetic head shown in FIG. 6 can also be used, for example, as a magnetic shield of a reproducing head (not shown) provided adjacent to the magnetic head. Then, in this case, the magnetic head of FIG. 6 can be formed on the return yoke RY after the formation of the reproducing head (not shown).
[0068]
That is, first, an electrode EL2 (thickness: 30 nm) made of molybdenum / tungsten (MoW) is formed on the return yoke RY. Next, a chromium (Cr) layer (film thickness: 5 nm) is formed as a base film of the hard magnetic layer C, and a cobalt platinum (CoPt) having a saturation magnetic flux density of 1 T (tesla) is formed thereon as the hard magnetic layer C. ) An alloy layer (thickness: 30 nm) is formed. This CoPt layer can be formed under the condition that the coercive force Hc is 1.5 KOe (kilo Oersted).
[0069]
Further, a copper (Cu) layer (thickness: 5 nm) is formed as the intermediate layer B2, and an iron-cobalt-nickel (FeCoNi) alloy layer having a saturation magnetic flux density of 2.3T is formed thereon as the soft magnetic layer A to a thickness of 10 nm. It forms so that it may become. Next, a copper (Cu) layer having a thickness of 15 nm is formed as the intermediate layer B1, and thereafter, patterning is performed in the track width direction.
[0070]
In patterning, an electron beam (EB) resist is patterned to a predetermined track width (for example, 50 nm), etched to the surface of the electrode EL2 by ion milling, and the MoW electrode EL2 is subjected to RIE (Reactive Ion) using a Freon-based gas.
Etching).
[0071]
Next, SiO2 is embedded so as to bury the etched portion (for example, the depth is about 95 nm). ₂ A film is formed, and the EB resist is lifted off. This allows the definition of the track width and the SiO ₂ The periphery of the track can be flattened by the insulating film.
[0072]
Next, in order to perform patterning on the back yoke side, a photoresist is formed with a width of about 3 μm as a mask. Then, similarly to the track width processing, etching is performed up to the electrode EL2 by using ion milling and RIE. Then, SiO 2 is used as the insulating layer IL. ₂ A film (thickness: 5 nm) is deposited, and a nickel iron (NiFe) alloy film (thickness: 90 nm) is deposited as a back yoke BY. ₂ A film (thickness: 25 nm) is formed and lifted off. In this manner, the back side can be buried with the insulating layer IL and the back yoke BY to be flattened. The back yoke BY is insulated from the hard magnetic layer C and the soft magnetic layer A by the insulating layer IL.
[0073]
Thereafter, a MoW alloy layer (film thickness 0.2 μm) is formed as the electrode EL1 and processed into an electrode shape. Thereafter, the hard magnetic layer C and the soft magnetic layer A appear on the ABS by performing a cutting and polishing process for forming a medium running surface (air bearing surface: ABS) like a normal head. Is completed.
[0074]
The magnetic head thus formed can appropriately generate the write magnetic field by inverting the current as described above with reference to FIGS. That is, by passing an electron current from the electrode EL1 toward the soft magnetic layer A via the hard magnetic layer C, spin-polarized electrons from the hard magnetic layer C flow into the soft magnetic layer A, The direction of the magnetization M of the magnetic layer A is the same as the direction of the magnetization M1 of the hard magnetic layer C.
[0075]
On the other hand, when an electron current flows from the electrode EL2 toward the electrode EL1, among the spin-polarized electrons incident on the interface of the hard magnetic layer C, those having a spin opposite to that of the hard magnetic layer C are The light is reflected and flows into the soft magnetic layer A. As a result, the magnetization M of the soft magnetic layer A faces in the opposite direction to the magnetization M1 of the hard magnetic layer C. That is, when the magnetization directions of the soft magnetic layer A and the hard magnetic layer C are opposite to each other, the magnetization reversal of the soft magnetic layer A does not occur, and when both directions are the same, the magnetization reversal occurs.
[0076]
Thus, by controlling the spin polarization direction of the electrons flowing into the soft magnetic layer A, the magnetization direction of the soft magnetic layer A having a high saturation magnetic flux density can be controlled. The soft magnetic layer A functions as a "recording magnetic pole" or a "writing magnetic pole" of the magnetic head.
[0077]
On the other hand, as the recording medium R, as shown, a perpendicular recording medium having a soft magnetic underlayer BL and a perpendicular magnetic recording layer RL can be used. The recording head of this embodiment can be caused to fly over the recording medium R at a flying height of 2 nm, for example. By using the recording medium provided with the soft magnetic backing layer BL, recording can be performed on the medium by the magnetic flux from the soft magnetic layer A having a high saturation magnetic flux density of 2.3 T, which is the recording magnetic pole of the magnetic head. . The coercive force Hc of the recording medium may be set so that recording is possible with the magnetic flux from the soft magnetic layer A and is not recorded with the magnetic flux from the hard magnetic layer C having a low saturation magnetic flux density.
[0078]
The recording magnetic flux emitted from the recording magnetic pole (soft magnetic layer A) records magnetization information on the recording layer RL of the recording medium, passes through the soft magnetic backing layer BL, is sucked up by the return yoke RY, and passes through the back yoke BY. Return to the recording pole.
[0079]
Here, in order to prevent writing other than when writing to the recording medium R, the magnetization M of the soft magnetic layer A is substantially perpendicular to the magnetization M1 of the hard magnetic layer C in a state where no current is flowing. A magnetic bias may be applied such that
[0080]
However, when a bias is applied to the soft magnetic layer A for stabilizing the magnetic domain, the torque required for the magnetization rotation increases. Therefore, it is necessary to increase the amount of current of the polarized electrons accordingly. In particular, when the magnetization of the soft magnetic layer A is rotated in the direction opposite to that of the magnetization fixed layer (the direction in which electrons flow from the soft magnetic layer A to the magnetization fixed layer), the electron reflection probability and the spin polarization rate in the magnetization fixed layer. Because of the problem described above, more electron current is required than in the case of magnetization rotation in the direction of the magnetization fixed layer.
[0081]
On the other hand, if the structure described above with reference to FIGS. 3 and 4 is adopted, the write current can be reduced.
[0082]
FIG. 7 is a schematic sectional view showing a magnetic head capable of reducing a write current. That is, the hard magnetic layers C1 and C2 are provided on both sides of the soft magnetic layer A via the intermediate layers B1 and B2, respectively. By setting the directions of the magnetizations M1 and M2 to be opposite to each other, the write current can be reduced as described above with reference to FIGS.
[0083]
Hereinafter, the magnetic head of this specific example will be described with reference to its manufacturing process.
[0084]
First, a read head (not shown) is formed, and a MoW layer (thickness: 30 nm) is formed as an electrode EL2 on the return yoke RY also serving as a magnetic shield.
[0085]
Next, a Cr layer (thickness: 5 nm) serving as a base film of the hard magnetic layer C2 is formed, and a CoPt alloy (thickness: 30 nm) having a saturation magnetic flux density of 1 T is formed thereon as the hard magnetic layer C2. This CoPt can be formed, for example, under the condition that the coercive force Hc is 1.5 KOe. Further, a copper (Cu) layer (thickness: 5 nm) is formed as the intermediate layer B2, and an FeCoNi alloy layer having a saturation magnetic flux density of 2.3 T is formed thereon as the soft magnetic layer A to a thickness of 10 nm. Further, a Co layer (thickness: 30 nm) having a saturation magnetic flux density of 1T is formed as the hard magnetic layer C1. The coercive force Hc of the hard magnetic layer C1 can be formed, for example, under the condition of 1 KOe.
[0086]
At this stage, the hard magnetic layer C1 is magnetized in the direction of the medium running surface (ABS) with a magnetic field of 2 KOe, and a magnetic field of 1.2 KOe is applied in a direction opposite to that of the ABS. Magnetize. Thus, the magnetization directions of the hard magnetic layers C1 and C2 can be made opposite to each other.
[0087]
Next, patterning in the track width direction is performed by the same steps as those described above with respect to the magnetic head shown in FIG. 6, and further, an insulating layer IL and a back yoke BY are formed.
[0088]
Thereafter, a MoW alloy layer (film thickness 0.2 μm) is formed as the electrode EL1 and processed into an electrode shape. Further, by performing a cutting and polishing process for forming a medium running surface, the hard magnetic material layers C1 and C2 and the soft magnetic material layer A magnetized in opposite directions appear on the ABS.
[0089]
As described above with reference to FIGS. 3 and 4, the magnetic head thus formed can reverse the recording magnetic field by the spin-polarized current. That is, by flowing an electron current from the electrode EL1 to the electrode EL2, the magnetization M of the soft magnetic layer A is in the same direction as the magnetization M1 of the hard magnetic layer C1. On the other hand, when an electron current flows from the electrode EL2 to the electrode EL1, the magnetization M of the soft magnetic layer A is directed to the direction of the magnetization M2 of the hard magnetic layer C2.
[0090]
At this time, among the spin-polarized electrons passing through the soft magnetic layer A, the electrons reflected at the interface of the hard magnetic layer again act on the soft magnetic layer A as described above with reference to FIG. The write effect is doubled, and the magnetization reversal of the soft magnetic layer A becomes possible with a small write current.
[0091]
On the other hand, in the present invention, instead of the hard magnetic material layer, a soft magnetic material layer magnetically fixed by an antiferromagnetic material layer can be used as the magnetization fixed layer.
[0092]
FIG. 8 is a schematic cross-sectional view illustrating a magnetic head fixed by magnetization with an antiferromagnetic layer. In this figure, the same elements as those described above with reference to FIGS. 1 to 7 are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0093]
In the case of the magnetic head of this specific example, the magnetization fixed layers C1 and C2 are each formed of a soft magnetic material. The magnetizations M1 and M2 are fixed by the antiferromagnetic layers AF1 and AF2 provided adjacent to these. Hereinafter, the structure of the magnetic head will be described with reference to its manufacturing process.
[0094]
First, an electrode EL2 (thickness: 30 nm) made of MoW is formed on a return yoke RY also serving as a magnetic shield of a reproducing head (not shown). Next, a platinum manganese (PtMn) alloy layer (thickness: 15 nm) is formed as the antiferromagnetic layer AF2, and NiFe having a saturation magnetization Bs of about 1T is formed thereon as a soft magnetic material constituting the magnetization fixed layer C2. An alloy layer is formed to a thickness of 10 nm. Further, a copper (Cu) layer (thickness: 5 nm) is formed as the intermediate layer B2, and a FeCoNi alloy layer having a saturation magnetic flux density of 2.3 T is formed thereon as the soft magnetic layer A to a thickness of 10 nm.
[0095]
Next, a Cu layer (thickness: 5 nm) is formed as the intermediate layer B1, and a 10 nm thick NiFe alloy layer having a saturation magnetization Bs of about 1 T is formed as a soft magnetic material constituting the pinned layer C1, and iridium is further formed thereon. An antiferromagnetic layer AF1 (thickness: 10 nm) made of a manganese (IrMn) alloy is formed.
[0096]
At this time, film formation was performed while applying a magnetic field in the direction in which the ABS (medium facing surface) was formed. That is, the heat treatment was performed at 270 ° C. for 10 hours while applying a magnetic field of 10 KOe in the opposite direction to the ABS. Thereby, the magnetization M2 of the magnetization fixed layer C2 made of a soft magnetic material adjacent to the PtMn alloy layer constituting the antiferromagnetic layer AF2 is fixed in the opposite direction to the ABS.
[0097]
Next, heat treatment was performed at 200 ° C. for 1 hour while applying a magnetic field of 10 KOe in the ABS direction. As a result, the magnetization M1 of the magnetization fixed layer C1 made of a soft magnetic material adjacent to the IrMn alloy layer constituting the antiferromagnetic layer AF1 is fixed in the ABS direction.
[0098]
By giving such a magnetization arrangement, when electrons flow from the magnetization pinned layer C1 which is magnetization-fixed in the ABS direction to the soft magnetic layer A which is a recording magnetic pole, the magnetization M of the soft magnetic layer A is oriented in the ABS direction. Conversely, when electrons flow into the soft magnetic layer A from the pinned layer C2, which is pinned in the opposite direction to the ABS, the magnetization M of the soft magnetic layer A is directed in the opposite direction to the ABS. .
[0099]
In this manner, the magnetization can be fixed by combining the antiferromagnetic layer and the thin soft magnetic layer instead of the hard magnetic substance. Further, only one of the pair of magnetization fixed layers C1 and C2 may be formed of a hard magnetic material.
[0100]
The magnetic head shown in FIGS. 6 to 8 has a structure in which the portion is buried with an insulating layer after processing in the track width direction. When a bias layer is buried in the portion buried with the insulating layer and the magnetization M of the soft magnetic layer A is magnetically biased in a direction parallel to the medium surface, a smooth and noise-free magnetization rotation can be obtained.
[0101]
9 to 12 are schematic cross-sectional views showing a magnetic head provided with such a bias layer. That is, these drawings are cross-sectional views as viewed from the medium facing surface.
[0102]
The magnetic head shown in FIGS. 9 to 12 has a structure in which the magnetization fixed layers C1 and C2 are fixed by the antiferromagnetic layers AF1 and AF2. Then, after processing the track width up to the electrode EL1, the soft magnetic material layer A is subjected to an orthogonal bias. ₂ An insulating layer IL of cobalt, a magnetic bias layer HM of cobalt platinum (CoPt), and SiO ₂ Can be formed by stacking insulating layers IL made of.
[0103]
The magnetization M of the soft magnetic layer A is biased in a direction substantially parallel to the medium facing surface by the bias magnetic field MB from the magnetic bias layer HM. In this manner, when the recording current is applied to reverse the magnetization M of the soft magnetic layer A to the magnetization direction of the magnetization fixed layer C1 or C2, the rotation amount of the magnetization is reduced to about 90 degrees, and the magnetization rotation is smooth. And also reduces magnetic noise. Further, it is possible to prevent the erasure of the medium information due to the magnetization of the soft magnetic layer A being oriented in the medium direction in the non-energized state.
[0104]
In the magnetic head shown in FIG. 9, after the track width processing has been performed up to the electrode EL1, ₂ Insulating layer IL (thickness: 7 nm), CoPt magnetic bias layer HM (thickness: 80 nm), SiO ₂ An insulating layer IL (film thickness: 20 nm) is formed, and finally an electrode EL2 is formed. The reason why the magnetic bias layer HM is covered with the insulating layer IL is to prevent the recording current from leaking to the magnetic bias layer HM and lowering the efficiency. By using a high-resistance hard magnetic material such as gamma hematite instead of CoPt as the material of the magnetic bias layer HM, the insulating layer IL can be omitted.
[0105]
The magnetic head shown in FIG. 10 has a structure in which track width processing is stopped at the intermediate layer B1. By doing so, the depth of the track width processing can be reduced, and as a result, errors in the track width due to the track width processing can be reduced. In addition, since the length of the minute region to be energized becomes short, heat generation is reduced, and as a result, a larger current is applied to cause reliable magnetization rotation of the soft magnetic layer A, and reliability associated with heat generation is reduced. Drop can be prevented. In FIG. 10, the entire intermediate layer B1 is processed, but the same effect can be obtained by processing the intermediate layer B1 halfway.
[0106]
In the case of the magnetic head shown in FIG. 11, the portion processed to the track width is limited to the intermediate layer B1, the soft magnetic layer A, and the intermediate layer B2. In this way, since the heat generation region can be limited to the portion of the soft magnetic layer A, the heat generation is reduced. As a result, a larger current is applied to cause the magnetization rotation of the soft magnetic layer A to occur reliably, Can be prevented from deteriorating in reliability.
[0107]
In this case, after the film is formed up to the intermediate layer B2, the track width is processed and the magnetic bias layer HM is formed, and the magnetization fixed layer C2 and the antiferromagnetic layer AF2 made of a soft magnetic material are formed again. it can.
[0108]
In the magnetic head shown in FIG. 12, after the film is formed up to the soft magnetic layer A, the track width is processed and the magnetic bias layer HM is formed, and then the intermediate layer B2 and the magnetization fixed layer C2 made of the soft magnetic material are formed. And an antiferromagnetic layer AF2. As described above, when the pair of magnetic bias layers HM is raised upward and the intermediate layer B2 is buried between them, the buried width (TW2) of the magnetization pinned layer C2 (soft magnetic material) to be buried next becomes the track width processing. Becomes smaller than the width (TW1) of the soft magnetic layer A. In this way, by reducing the width of one magnetization pinned layer C2, the current-carrying region in the soft magnetic layer A can be limited. For this reason, the substantial width of the magnetic pole can be made smaller than the track width processing size using lithography, and higher-density magnetic recording becomes possible.
[0109]
(Second embodiment)
FIG. 13 is a plan view of a recording magnetic head according to a second embodiment of the present invention as viewed from the medium facing surface. 14 is a sectional view taken along line AA of FIG. 13, and FIG. 15 is a sectional view taken along line BB of FIG. Also in these drawings, the same elements as those described above with reference to FIGS. 1 to 12 are denoted by the same reference numerals, and detailed description is omitted. Here, the “depth direction” means a direction perpendicular to the medium facing surface ABS.
[0110]
As can be seen from FIG. 13, in the magnetic head of this embodiment, the front end of the soft magnetic layer A acting as a recording magnetic pole is exposed on the medium facing surface, and the periphery is covered with the insulating layer IL.
[0111]
On the other hand, as can be seen from FIGS. 14 and 15, magnetization fixed layers C1 and C2 are provided above and below the soft magnetic layer A via intermediate layers B1 and M2. These magnetization fixed layers C1 and C2 are made of a hard magnetic material, and their magnetizations are fixed in antiparallel directions to each other.
[0112]
When an electron current is passed through the magnetic head from the electrode EL1 to the electrode EL2, the magnetization of the soft magnetic layer A is directed to the direction of the magnetization of the magnetization fixed layer C1. On the other hand, when an electron current flows from the electrode EL2 to the electrode EL1, the magnetization of the soft magnetic layer A is directed to the direction of the magnetization of the magnetization fixed layer C2.
[0113]
Hereinafter, the magnetic head of this embodiment will be described in more detail with reference to the manufacturing process.
[0114]
First, an alumina insulating layer (not shown) is formed to a thickness of about 0.2 μm on an upper shield (not shown) of a read head (not shown), and an electrode EL2 (0.1 μm thick) made of a MoW alloy is formed. ) Is formed. The MoW layer is etched into an electrode pattern using a photoresist. That is, the surface of the alumina film is etched by RIE using a Freon-based gas, alumina is newly buried around the surface by 0.1 μm, and the resist is lifted off for flattening.
[0115]
Next, a Cr layer (thickness: 5 nm) serving as a base of the magnetization fixed layer C2 is formed, and a CoPt alloy (thickness: 30 nm) having a saturation magnetic flux density of 1 T is formed thereon as a hard magnetic material constituting the magnetization fixed layer C2. Form. Here, the CoPt can be formed under the condition that the coercive force Hc is 1.5 KOe. Further, a Cu layer (thickness: 5 nm) is formed as the intermediate layer B2. Here, the magnetization fixed layer C2 is magnetized in a direction opposite to the ABS by a magnetic field of 2KOe.
[0116]
After forming the laminated film up to this point, patterning is performed with a photoresist having a width and a length of 1 μm each. This is etched by ion milling to Cu of the intermediate layer B2, CoPt of the magnetization fixed layer C2 (set to Bs-1T, Hc-1.5KOe) and Cr of the base, and MoW thereunder is replaced with Freon-based gas. The surface of the alumina film is etched by the used RIE. Thereafter, an alumina film is formed to a thickness of about 40 nm, and the photoresist is lifted off to form a flat surface surrounded by an alumina insulating film around the metal laminated film of 1 micron square.
[0117]
Next, an FeCoNi alloy layer (thickness: 10 nm: Bs to 2.3T) is formed as the soft magnetic layer A serving as the recording magnetic pole. This alloy layer is patterned by EB lithography so as to have a width of 40 nm and a length of 1.5 μm, and to be arranged at a central position of a metal laminated film (1 μm square) below in a length direction of 0.25 μm. I do.
[0118]
Next, the FeCoNi alloy layer (soft magnetic layer A) is etched using ion milling. Thereafter, an alumina layer (film thickness: 10 nm) is formed, and the resist is lifted off. By this step, the soft magnetic layer A (recording magnetic pole) made of a FeCoNi alloy of 40 nm × 1.5 μm was placed in electrical contact with the intermediate layer B2, and the periphery thereof was flattened with an alumina insulating film. Become.
[0119]
Next, a Cu layer (thickness: 5 nm) is formed as the intermediate layer B1, and a Co layer (thickness: 30 nm) having a saturation magnetic flux density of 1T is formed thereon as a hard magnetic material constituting the magnetization fixed layer C1. The coercive force Hc of the magnetization fixed layer C1 can be formed under the condition of 1 KOe. At this point, a magnetic field of 1.2 KOe is applied in the ABS direction to magnetize the pinned layer C1, and the magnetization directions of the pinned layers C1 and C2 are applied in opposite directions.
[0120]
Next, a 1 μm square photoresist mask is formed, and the intermediate layer B1 and the magnetization fixed layer C1 are etched by ion milling. Further, an alumina film having a thickness of 35 nm is formed, lifted off, and flattened. Then, a MoW alloy layer (thickness: 0.1 μm) is formed thereon as an electrode EL1, and is patterned into an electrode shape by RIE using a Freon-based gas.
[0121]
An ABS is formed by cutting and polishing the laminate thus formed at a predetermined location. At this time, as shown in FIG. 13, only the recording magnetic pole (soft magnetic layer A) appears on the ABS with a track width of 40 nm and a thickness of 10 nm.
[0122]
Through the above processing process, the electrodes EL1 and EL2 are electrically connected, and a recording head in which only the recording magnetic pole appears on the ABS is formed. With such a structure, writing due to the flow of the electron current from the medium other than the recording magnetic pole (soft magnetic layer A) to the medium and writing to the medium due to the magnetic field from the magnetization fixed layers (C1, C2) are prevented. be able to.
[0123]
FIG. 16 is a schematic cross-sectional view illustrating a state in which writing is performed on the recording medium R. In accordance with the direction of the current flowing between the electrodes EL1 and EL2, the magnetization M of the soft magnetic layer A is set to one of the magnetizations M1 and M2 of the magnetization fixed layers C1 and C2. As described above, by controlling the inflow direction of electrons flowing into the soft magnetic layer A, the direction of the magnetization M of the soft magnetic layer A having a hard saturation magnetic flux density can be controlled. Then, a recording bit can be formed on the magnetic recording layer RL on the recording medium R by the magnetization M.
[0124]
Further, as illustrated in FIG. 17, only one layer of the magnetization fixed layer C may be provided. Also in this case, as described above with reference to FIGS. 1 and 2, the direction of the magnetization M of the soft magnetic layer A can be controlled by the direction of current flow.
[0125]
Also in this embodiment, as the magnetization fixed layers C1 and C2, instead of the hard magnetic material, a soft magnetic material magnetization-fixed by an antiferromagnetic material can be used.
[0126]
FIG. 18 and FIG. 19 are schematic cross-sectional views showing a magnetic head magnetized and fixed by an antiferromagnetic material. That is, these figures are cross-sectional views corresponding to FIGS. 14 and 15, respectively. The horizontal direction in FIG. 18 corresponds to the depth direction (the direction perpendicular to the medium facing surface ABS), and the horizontal direction in FIG. 19 corresponds to the width direction of the recording track.
The arrow TW in FIG. 18 corresponds to the width direction of the recording track.
[0127]
As shown in these figures, the magnetization fixed layers C1 and C2 are formed of a soft magnetic material, and magnetization is fixed by the adjacent antiferromagnetic layers AF1 and AF2. Here, the antiferromagnetic material layer AF1 shown in FIG. 19 is magnetized in the front direction of the drawing, and the antiferromagnetic material layer AF2 is magnetized in the depth direction of the drawing.
[0128]
Magnetic bias layers HM for biasing the magnetization M of the soft magnetic layer A in a direction orthogonal to the magnetization directions of the magnetization fixed layers C1 and C2 are provided on both sides of the soft magnetic layer A. . The magnetic bias layer HM can be formed of a high-resistance hard magnetic material such as gamma hematite.
[0129]
As shown in FIG. 19, by patterning the soft magnetic layer A in the track width direction, the recording current flows intensively to the soft magnetic layer A in this portion, so that heat generation can be minimized. . Further, since only the recording magnetic pole (soft magnetic layer A) appears on the medium running surface, it is possible to prevent current from leaking from the magnetization fixed layer or the like to the recording medium. Further, since the orthogonal bias is applied to the soft magnetic layer A by the magnetic bias layer HM having a high electric resistance, the magnetization rotation becomes smooth, and recording other than at the time of writing can be prevented.
[0130]
Here, returning to FIGS. 16 and 17 again, as the recording medium R, a perpendicular recording medium having a perpendicular recording layer RL in which a conductive backing layer BL is provided on the back surface side can be used. The recording head may be run on the medium while being separated by a predetermined flying height, or may be run while being substantially in contact with the recording head.
[0131]
As described above, the electrons flowing from the electrodes EL1 or EL2 determine the direction of the magnetization M of the soft magnetic layer A according to the flowing direction. Further, when the recording head is run in a contact state, the soft magnetic layer A (recording magnetic pole) and the medium R are in electrical contact with each other, so that the electron spin-polarized in the magnetization M direction of the soft magnetic layer A. Flows into the recording layer RL and flows out into the conductive backing layer BL. Due to the spin-polarized electrons, the recording layer RL of the recording medium R aligns spins in that direction, and as a result, magnetization is recorded in the same direction as the soft magnetic layer A. In other words, in the case of contact running, the direction of the magnetization M of the soft magnetic layer A is controlled by passing a current from the electrode EL1 or EL2, and the spin-polarized electrons are passed from the soft magnetic layer A to the medium R to cause the medium to rotate. Information can be more efficiently written to the recording layer RL.
[0132]
When writing magnetically, it is desirable to use an FeCoNi alloy having a saturation magnetization Bs of about 2.3 T (tesla) as the soft magnetic layer A. However, when spin-polarized electrons are caused to flow through a recording medium by contact traveling, writing by spin transfer from spin-polarized electrons can also be used. Therefore, the material of the soft magnetic layer A is not limited to a high Bs material, but may be an FeNi alloy or the like from which soft magnetism can be easily obtained. The use of a material from which soft magnetism can be easily obtained can reduce the reversal current of the soft magnetic layer A and reduce heat generation.
[0133]
Note that, as described above with reference to FIG. 6, even when the soft under layer BL is provided on the recording medium R, the same effect can be obtained if the conductivity of the under layer can be ensured.
[0134]
In the case of recording with spin-polarized electrons flowing from the soft magnetic layer A to the medium R by contact traveling, the return yoke RY and the back yoke BY as illustrated in FIG. 6 are not essentially required. This simplifies the structure of the magnetic head, and facilitates the formation of finer patterns such as track width. In addition, the manufacturing yield is increased, and there is a cost advantage.
[0135]
(Third embodiment)
Next, as a third embodiment of the present invention, a magnetic head that performs reproduction by using a spin-polarized electron current will be described.
[0136]
FIG. 20 is a schematic sectional view showing a magnetic head according to the third embodiment of the present invention. Also in this figure, the same elements as those described above with reference to FIGS. 1 to 19 are denoted by the same reference numerals, and detailed description is omitted.
[0137]
In the case of the magnetic head of the present embodiment, an insulating layer IL is provided between the magnetization fixed layer C and the soft magnetic layer A, and the magnetization fixed layer C and the soft magnetic layer are formed by the minute holes NH formed in the insulating layer IL. It is in contact with the body layer A. Although only one minute hole NH is shown in FIG. 20, the present invention is not limited to this, and a plurality of minute holes NH may be provided. The magnetization fixed layer C can be formed of, for example, a hard magnetic material.
[0138]
In the case of the reproducing magnetic head, as described above with reference to FIG. 5, the magnetization of the recording bit can be read by the change in the current conductance through the minute hole NH.
[0139]
When the magnetic head is driven to contact the medium R, the medium R is electrically grounded, and an electric circuit in which the potential of the electrode EL1 of the magnetic head is higher than the ground (ground potential) is formed. Electrons flow from R into the soft magnetic layer A. That is, spin-polarized electrons corresponding to the recording magnetization of the recording layer RL flow into the soft magnetic layer A. Then, the direction of the magnetization M of the soft magnetic layer A is controlled by the spin-polarized electrons. As a result, when the recording magnetization of the recording layer RL is in the same direction as the magnetization fixed layer C, the conductance is Cp (small resistance), and when the recording magnetization is in the opposite direction, the conductance is Cap (large resistance).
[0140]
In the case of reading using spin-polarized electrons, it is possible to prevent a signal magnetic field from side-reading by appropriately increasing the coercive force Hc of the soft magnetic layer A, and to read a recording signal of only recording bits in electrical contact. it can. As described above, if the magnetization M of the soft magnetic layer A is rotated by the torque generated by the spin-polarized electrons, it is easy to read the signal magnetic field of only the recording bit that is in contact, and the magnetic flux is detected. Compared with a signal reproducing method, the method is more resistant to external disturbances, has better resolution, and does not require a shield in the track width direction or the track length direction.
[0141]
Next, the manufacturing process of the magnetic head of this embodiment will be described.
[0142]
First, an alumina insulating layer (thickness: about 0.2 μm) is formed on a substrate (not shown) (not shown). Next, an FeNi alloy layer (thickness: 5 nm) serving as a current collector is formed as the soft magnetic layer A. Furthermore, on top of that, SiO ₂ A layer (thickness: 5 nm) is formed as an insulating layer IL. Next, patterning is performed to a width of 40 nm and a length of 1.5 μm by EB lithography. Next, using the resist mask by ion milling, ₂ The layer and the FeNi alloy layer (soft magnetic layer A) are etched. Thereafter, an alumina layer (film thickness: 10 nm) is formed, and the resist is lifted off. By this step, a soft magnetic layer A made of a 40 nm × 1.5 μm FeNi alloy and SiO 2 ₂ Is patterned and flattened.
[0143]
Next, XeF is applied to the surface of the insulating layer IL in a vacuum. ₂ Irradiating electron beam (EB) with a diameter of about 5 nm while blowing gas with a nozzle ₂ A minute hole NH having a diameter of about 5 nm is formed in the insulating layer IL.
[0144]
Next, a cobalt (Co) layer (thickness: 30 nm) having a saturation magnetic flux density of 1 T is formed as the magnetization fixed layer C. The coercive force Hc of the magnetization fixed layer C was formed under the condition of 1 KOe. At this time, a magnetic field of 1.2 KOe was applied to magnetize the magnetization fixed layer C in the ABS direction.
[0145]
This is cut and polished to form an ABS as described above with reference to the first embodiment. At this time, as described above with respect to the second embodiment, the ABS is formed so that only the soft magnetic layer A serving as a current collector appears with a track width of 40 nm and a thickness of 5 nm. Through the above-described process, the electrode EL1 is electrically connected to the soft magnetic layer A, and a read magnetic head in which only the tip of the soft magnetic layer A serving as a read collector appears is formed on the ABS. You.
[0146]
(Fourth embodiment)
Next, as a fourth embodiment of the present invention, a description will be given of a spin-polarized current detection type magnetic head capable of performing stable reproduction even when the contact state with the recording medium fluctuates.
[0147]
FIG. 21 is a schematic sectional view showing a magnetic head according to a fourth embodiment of the present invention. Also in this figure, the same elements as those described above with reference to FIGS. 1 to 20 are denoted by the same reference numerals, and detailed description thereof will be omitted.
[0148]
In the magnetic head of this embodiment, the magnetization fixed layers C1 and C2 are provided on both sides of the soft magnetic layer A, and these are in contact with each other by the minute holes NH formed in the insulating layer IL.
[0149]
Also in this magnetic head, the conductance when a current flows from the soft magnetic layer A to the electrode EL1 depends on the relative direction between the magnetization M of the soft magnetic layer A and the magnetization M1 of the magnetization fixed layer C1. In the case of the specific example shown in FIG. 21, if the direction of the magnetization M of the soft magnetic layer A is directed to the ABS direction, the direction becomes parallel to the magnetization M1 of the magnetization fixed layer C1. Accordingly, since there is no domain wall at the interface (the minute hole NH) between the magnetization fixed layer C1 and the soft magnetic layer A, electrons move without being scattered. The conductance at this time is defined as Cp.
[0150]
On the other hand, in this case, since the magnetization M of the soft magnetic material layer A and the magnetization M2 of the magnetization fixed layer C2 are in opposite directions, the contact portion is narrowed at the interface by the minute hole NH, so that it is sharp. Domain walls exist. For this reason, the electrons are scattered by the domain wall, and the conductance Cap decreases. As a result, when the conductances on both sides are compared, Cp> Cap.
[0151]
When the magnetic head is brought into contact with the recording medium R in a state where the recording medium R is electrically grounded and the potentials of the electrodes EL1 and EL2 are higher than the ground potential, a spin bias corresponding to the magnetization direction of the recording layer RL is obtained. Polar electrons flow from the medium into the soft magnetic layer A, and determine the magnetization M of the soft magnetic layer A. Further, the electrons that have flowed into the soft magnetic layer A are diverted to the electrodes EL1 and EL2 according to the above-described conductance. In this case, the direction of magnetization of the soft magnetic layer A can be determined by examining the two conductance ratios of the electrodes EL1 and EL2. For this reason, the influence of the contact resistance between the recording medium R and the soft magnetic layer A can be eliminated, and reproduction with a high S / N can be performed.
[0152]
Next, the manufacturing process of the magnetic head of this embodiment will be described.
[0153]
First, an electrode EL2 (0.1 μm thick) made of a MoW alloy is formed on an alumina insulating layer (thickness: about 0.2 μm) not shown. The MoW layer is etched to the surface of the alumina insulating layer by RIE using a Freon-based gas using a photoresist as a mask to form an electrode pattern.
[0154]
Next, alumina is buried around the electrode EL2 to a thickness of about 0.1 μm, and the resist is lifted off to be flattened. Next, a Cr layer (thickness: 5 nm) serving as a base of the magnetization fixed layer C2 is formed, and a CoPt alloy layer (thickness: 30 nm) having a saturation magnetic flux density of 1T is formed thereon as the magnetization fixed layer C2. This CoPt layer can be formed under the condition that the coercive force Hc is 1.5 KOe.
[0155]
Next, SiO 2 is used as the insulating layer IL2. ₂ A layer (5 nm in thickness) is formed. Here, by applying a magnetic field of 2 KOe, the magnetization fixed layer C2 is magnetized in the opposite direction to the ABS. Next, the laminated structure is patterned with a photoresist having a width and a length of 1 μm each. Next, the SiO 2 of the insulating layer IL2 is formed by ion milling. ₂ The layer and the CoPt layer (set to Bs-1T, Hc-1.5KOe) of the magnetization fixed layer C2 and the Cr layer of the underlying film are etched. Then, an alumina layer is formed to a thickness of about 40 nm, and the photoresist is lifted off, thereby forming a flat surface surrounded by an alumina insulating layer around the metal laminated film of 1 micron square.
[0156]
Next, while spraying a XeF2 gas with a nozzle on the surface of the insulating layer IL2 in a vacuum, an electron beam (EB) narrowed down to a diameter of about 5 nm is irradiated to form SiO2. ₂ A fine hole NH having a diameter of about 5 nm is formed in the insulating layer IL2 made of.
[0157]
Next, an FeNi alloy layer (10 nm in thickness, Hc <1 Oe) serving as the soft magnetic layer A is formed. Further thereon, as the insulating layer IL1, SiO 2 is used. ₂ A layer (5 nm in thickness) is formed. Next, patterning is performed by EB lithography so as to have a width of 40 nm and a length of 1.5 μm so as to reach the center position of the metal laminated film (1 μm square) in the length direction by 0.25 μm.
[0158]
Next, the FeNi alloy film (soft magnetic layer A) is etched by ion milling using the resist mask. Thereafter, an alumina layer (film thickness: 10 nm) is formed, and the resist is lifted off. By this step, the periphery of the soft magnetic layer A (current collector) made of the FeNi alloy of 40 nm × 1.5 μm was flattened with the alumina insulating layer.
[0159]
Next, while spraying a XeF2 gas with a nozzle on the surface of the insulating layer IL1 in a vacuum, an electron beam (EB) narrowed to a diameter of about 5 nm is irradiated to SiO2. ₂ A minute hole NH having a diameter of about 5 nm is formed in the insulating layer IL1 made of.
[0160]
Next, a cobalt (Co) layer (thickness: 30 nm) having a saturation magnetic flux density of 1 T is formed as the magnetization fixed layer C1. The coercive force Hc of the magnetization fixed layer C1 can be formed, for example, under the condition of 1 KOe. At this time, a magnetic field of 1.2 KOe is applied to magnetize the magnetization fixed layer C1 in the ABS direction so that the magnetization directions of the magnetization fixed layer C1 and the magnetization fixed layer C2 are opposite to each other.
[0161]
Next, a 1 μm square photoresist mask is formed, and the insulating layer IL1, the underlying layer, and the magnetization fixed layer C1 are etched by ion milling. Further, an alumina layer is formed to a thickness of 40 nm, and lift-off is performed for flattening. Further, a MoW alloy layer (thickness: 0.1 μm) is formed thereon as an electrode EL1, and is patterned into an electrode shape by RIE using a Freon-based gas.
[0162]
This is cut and polished to form an ABS as described above with reference to the first embodiment. At this time, as described above with respect to the second embodiment, the ABS is formed so that only the soft magnetic layer A serving as a current collector appears with a track width of 40 nm and a thickness of 10 nm. Through the above-described process, the electrodes EL1 and EL2 are electrically connected, and a read magnetic head in which only the tip of the soft magnetic layer A serving as a read collector is formed on the ABS is formed.
[0163]
(Fifth embodiment)
Next, as a fifth embodiment of the present invention, a recording / reproducing magnetic head in which a recording magnetic head and a reproducing magnetic head are combined will be described.
[0164]
FIG. 22 is a schematic sectional view showing a magnetic head according to a fifth embodiment of the present invention. Also in this figure, the same elements as those described above with reference to FIGS. 1 to 21 are denoted by the same reference numerals, and detailed description is omitted.
[0165]
The magnetic head of this embodiment can perform recording and reproduction in a state where the magnetic head is floated from the medium R by a predetermined flying height. However, recording and reproduction can be performed in the same manner even when the vehicle runs in contact.
[0166]
First, the recording head operates on the same principle as that described above with reference to FIG. That is, by passing an electron current from the electrode EL1 toward the electrode EL2 through the pinned layer C1 and the minute hole NH, the magnetization M of the soft magnetic layer 3 is in the same direction as the direction of the magnetization M1 of the pinned layer C1. Turn to. On the other hand, when an electron current flows from the electrode EL2 to the electrode EL1 via the magnetization fixed layer C2, the magnetization M of the soft magnetic layer A is directed to the direction of the magnetization M2 of the magnetization fixed C2. As described above, by controlling the spin polarization direction of the electrons flowing into the high Bs soft magnetic material layer A, the direction of the magnetization M of the soft magnetic material layer A serving as the recording magnetic pole is controlled regardless of the presence or absence of the minute holes NH. it can.
[0167]
On the other hand, as for the reproducing head, the resistance value can be reproduced by the current conductance of the portion where the minute hole NH is provided. That is, the magnetization M of the soft magnetic layer A is rotated by the signal magnetic field from the recording layer RL of the medium R. When the direction of the magnetization M of the soft magnetic layer A is parallel to the magnetization pinned layer C1, the minute holes NH show a low resistance, and when the magnetizations (M and M1) on both sides thereof are antiparallel, a high resistance is obtained. Show. That is, since the change in conductance between the magnetization fixed layer C1 and the soft magnetic layer A via the minute holes NH is large, the magnetic head is substantially formed by the parallel / anti-parallel relationship of the magnetization of these two magnetic layers. Is determined.
[0168]
However, the sense current for detecting such a resistance change needs to be kept lower than during recording so that the magnetization M of the soft magnetic layer A is not reversed by the spin injection torque due to the sense current. That is, the recording / reproducing type magnetic head of this embodiment can use the recording operation and the reproducing operation selectively by using a large magnetic current (at the time of recording) and small (at the time of reproduction) while using the same magnetic element structure.
[0169]
FIG. 23 is a schematic cross-sectional view illustrating a magnetic head according to a modification of the present embodiment. Also in this figure, the same elements as those described above with reference to FIGS. 1 to 22 are denoted by the same reference numerals, and detailed description will be omitted.
[0170]
The magnetic head of this embodiment has a structure in which the recording head described above with reference to FIG. 16 and the reproducing head described above with reference to FIG. 22 are combined.
[0171]
That is, a predetermined recording current flows between the electrodes EL1 and EL2 as the recording head. As described above with reference to FIG. 20, electrons having a predetermined spin polarization flow into the soft magnetic layer A according to the direction of the current, and rotate the magnetization M in the corresponding direction. Further, part of the spin-polarized electrons flows from the soft magnetic layer A into the recording layer RL of the recording medium, and acts on the magnetization of the recording bit. That is, by flowing the spin-polarized electrons to the recording layer RL, recording can be performed with the magnetization directed in a predetermined direction. At this time, a write magnetic field due to the magnetization of the soft magnetic layer A may be used together.
[0172]
On the other hand, the reproducing head operates in the same manner as described above with reference to FIG. That is, since the change in conductance between the magnetization fixed layer C1 and the soft magnetic layer A via the minute holes NH is large, the magnetization is substantially due to the parallel / anti-parallel relationship between the two magnetic layers. The reproduction output of the magnetic head is determined.
[0173]
Note that the same operation as the magnetic head shown in FIG. 20 can be performed as the reproducing head. That is, the soft magnetic layer A receives spin-polarized electrons corresponding to the magnetization from the recording layer RL of the medium R, rotates the magnetization M, and detects a change in conductance through the minute holes NH. The magnetization of the recording bit of the RL can be detected.
[0174]
(Sixth embodiment)
Next, a description will be given of a magnetic recording / reproducing apparatus equipped with the magnetic head described above as a sixth embodiment of the present invention. That is, the above-described magnetic head of the present invention can be incorporated in, for example, a recording / reproducing integrated magnetic head assembly and mounted on a magnetic recording / reproducing apparatus.
[0175]
FIG. 24 is a perspective view of an essential part illustrating a schematic configuration of such a magnetic recording / reproducing apparatus. That is, the magnetic recording / reproducing device 150 of the present invention is a device using a rotary actuator. In the figure, a recording medium disk 200 is mounted on a spindle 152 and is rotated in the direction of arrow A by a motor (not shown) responsive to a control signal from a drive controller (not shown). The magnetic recording / reproducing device 150 of the present invention may include a plurality of media disks 200.
[0176]
A head slider 153 for recording and reproducing information stored in the medium disk 200 is attached to a tip of a thin-film suspension 154. Here, the head slider 153 has, for example, one of the above-described magnetic heads mounted near the tip thereof.
[0177]
When the medium disk 200 rotates, the medium facing surface (ABS) of the head slider 153 is held with a predetermined flying height from the surface of the medium disk 200. Alternatively, a “contact traveling type” in which the slider contacts the medium disk 200 may be used.
[0178]
The suspension 154 is connected to one end of an actuator arm 155 having a bobbin for holding a drive coil (not shown). At the other end of the actuator arm 155, a voice coil motor 156, which is a type of linear motor, is provided. The voice coil motor 156 includes a drive coil (not shown) wound around a bobbin portion of the actuator arm 155, and a magnetic circuit including a permanent magnet and an opposing yoke which are arranged opposite to sandwich the coil.
[0179]
The actuator arm 155 is held by ball bearings (not shown) provided at two positions above and below the spindle 157, and can be rotated and slid by a voice coil motor 156.
[0180]
FIG. 25 is an enlarged perspective view of the magnetic head assembly ahead of the actuator arm 155 viewed from the disk side. That is, the magnetic head assembly 160 has an actuator arm 155 having, for example, a bobbin for holding a drive coil, and the suspension 154 is connected to one end of the actuator arm 155.
A head slider 153 having one of the magnetic heads described above with reference to FIGS. 1 to 23 is attached to the tip of the suspension 154. The suspension 154 has leads 164 for writing and reading signals, and the leads 164 are electrically connected to the respective electrodes of the magnetic head incorporated in the head slider 153. In the figure, reference numeral 165 denotes an electrode pad of the magnetic head assembly 160.
[0181]
According to the present invention, by providing the magnetic head as described above with reference to FIGS. 1 to 23, information is magnetically recorded on the medium disk 200 at a higher recording density than before, or the recorded information is highly recorded. It becomes possible to read reliably with sensitivity.
[0182]
Also in this embodiment, as the magnetization fixed layers C1 and C2, a hard magnetic material may be used, or a soft magnetic material magnetization-fixed by an antiferromagnetic material may be used.
[0183]
The embodiments of the invention have been described with reference to examples. However, the present invention is not limited to these specific examples. For example, those skilled in the art can appropriately select specific materials such as a ferromagnetic layer, an insulating layer, an antiferromagnetic layer, a nonmagnetic metal layer, an electrode, and the like, a film thickness, a shape, and a dimension which constitute a magnetic head. By doing so, the present invention can be implemented in the same manner and a similar effect can be obtained, which is included in the scope of the present invention.
[0184]
Further, the magnetic recording / reproducing apparatus using the present invention may be a so-called fixed type having a specific recording medium constantly, or a so-called “removable” type in which the recording medium can be replaced.
[0185]
In addition, all magnetic heads that can be implemented by a person skilled in the art with appropriate design changes based on the magnetic head described above as an embodiment of the present invention also belong to the scope of the present invention.
[0186]
【The invention's effect】
As described above in detail, according to the present invention, the magnetization of the soft magnetic material layer can be reversed in a predetermined direction by a current direct drive type magnetization reversal mechanism using a spin-polarized current. For this reason, a much faster magnetization reversal becomes possible as compared with a conventional magnetic head using a leakage current magnetic field from a coil. As a result, a high operating frequency required for ultra-high-density magnetic recording can be realized. Furthermore, the size can be significantly reduced as compared with the case where the coil is used, and the track width and the recording bit size can be easily reduced.
[0187]
That is, according to the present invention, a magnetic head having a higher recording density than the conventional one can be provided, and the industrial advantage is great.
[Brief description of the drawings]
FIG. 1 is a schematic view illustrating a basic cross-sectional structure of a main part of a recording magnetic head according to an embodiment of the present invention.
FIG. 2 is a schematic diagram illustrating a mechanism of magnetization reversal in the magnetic head of FIG. 1;
FIG. 3 is a schematic view illustrating a basic cross-sectional structure of a main part of a magnetic head according to another embodiment of the present invention.
FIG. 4 is a schematic sectional view for explaining a mechanism of “magnetization reversal” in the magnetic head shown in FIG. 3;
FIG. 5 is a schematic sectional view showing a reproducing magnetic head according to the embodiment of the present invention.
FIG. 6 is a cross-sectional view illustrating a main part of a recording magnetic head according to the first embodiment of the present invention.
FIG. 7 is a schematic sectional view illustrating a magnetic head capable of reducing a write current.
FIG. 8 is a schematic cross-sectional view illustrating a magnetic head fixed by magnetization with an antiferromagnetic layer.
FIG. 9 is a schematic sectional view showing a magnetic head provided with a magnetic bias layer.
FIG. 10 is a schematic sectional view showing a magnetic head provided with a magnetic bias layer.
FIG. 11 is a schematic sectional view showing a magnetic head provided with a magnetic bias layer.
FIG. 12 is a schematic sectional view showing a magnetic head provided with a magnetic bias layer.
FIG. 13 is a plan view of a recording magnetic head according to a second embodiment of the present invention as viewed from a medium facing surface.
FIG. 14 is a sectional view taken along line AA of FIG.
FIG. 15 is a sectional view taken along line BB of FIG. 13;
FIG. 16 is a schematic cross-sectional view illustrating a state in which writing is performed on a recording medium R.
FIG. 17 is a schematic cross-sectional view showing a magnetic head having only one pinned layer C;
FIG. 18 is a schematic cross-sectional view showing a magnetic head fixed by magnetization with an antiferromagnetic material.
FIG. 19 is a schematic cross-sectional view showing a magnetic head fixed by magnetization with an antiferromagnetic material.
FIG. 20 is a schematic sectional view showing a magnetic head according to a third embodiment of the present invention.
FIG. 21 is a schematic sectional view illustrating a magnetic head according to a fourth embodiment of the present invention.
FIG. 22 is a schematic sectional view illustrating a magnetic head according to a fifth embodiment of the present invention.
FIG. 23 is a schematic sectional view showing a magnetic head according to a modification of the fifth embodiment.
FIG. 24 is a perspective view of an essential part illustrating a schematic configuration of a magnetic recording / reproducing apparatus.
FIG. 25 is an enlarged perspective view of the magnetic head assembly ahead of the actuator arm 155 as viewed from the disk side.
[Explanation of symbols]
150 Magnetic recording / reproducing device
152 spindle
153 Head slider
154 suspension
155 Actuator arm
156 Voice coil motor
157 spindle
160 magnetic head assembly
164 lead wire
200 media disk
A Soft magnetic layer
ABS medium facing surface
AF1, AF2 Antiferromagnetic layer
B, B1, B2 Intermediate layer
BL backing layer
BY back yoke
C, C1, C2 magnetization fixed layer
EL1, EL2 electrodes
I current
IL, IL1, IL2 insulating layer
M, M1, M2 magnetization
HM magnetic bias layer
MB bias magnetic field
NH micro hole
R recording medium
RL magnetic recording layer
RY return yoke

Claims (13)

A first ferromagnetic layer having a magnetization substantially fixed in a first direction;
A second ferromagnetic layer whose magnetization direction is variable;
A first intermediate layer provided between the first ferromagnetic layer and the second ferromagnetic layer;
With
A current is caused to flow between the first and second ferromagnetic layers to cause spin-polarized electrons to act on the second ferromagnetic layer, thereby changing the direction of magnetization of the second ferromagnetic layer to the current. Determine the direction according to the direction of
A magnetic head, wherein information can be magnetically recorded on a magnetic recording medium by a recording magnetic field generated by the determined magnetization of the second ferromagnetic layer. A first ferromagnetic layer having a magnetization substantially fixed in a first direction;
A second ferromagnetic layer whose magnetization direction is variable;
A first intermediate layer provided between the first ferromagnetic layer and the second ferromagnetic layer;
With
A current is caused to flow between the first and second ferromagnetic layers to cause spin-polarized electrons to act on the second ferromagnetic layer, thereby changing the direction of magnetization of the second ferromagnetic layer to the current. Determine the direction according to the direction of
A magnetic head characterized in that information can be recorded by determining the magnetization of the magnetic recording medium by flowing the spin-polarized electrons from the second ferromagnetic layer to the magnetic recording medium. When an electron current flows from the first ferromagnetic layer to the second ferromagnetic layer, the direction of the magnetization of the second ferromagnetic layer is the first direction,
When an electron current flows from the second ferromagnetic layer to the first ferromagnetic layer, the direction of the magnetization of the second ferromagnetic layer is opposite to the first direction. The magnetic head according to claim 1, wherein the direction is set to a direction. A first ferromagnetic layer having a magnetization substantially fixed in a first direction;
A third ferromagnetic layer having a magnetization substantially fixed in a second direction opposite to the first direction;
A second ferromagnetic layer provided between the first ferromagnetic layer and the third ferromagnetic layer and having a variable direction of magnetization;
A first intermediate layer provided between the first ferromagnetic layer and the second ferromagnetic layer;
A second intermediate layer provided between the second ferromagnetic layer and the third ferromagnetic layer;
With
A current is caused to flow between the first and third ferromagnetic layers to cause spin-polarized electrons to act on the second ferromagnetic layer to change the direction of magnetization of the second ferromagnetic layer. Determine the direction according to the direction,
A magnetic head, wherein information can be magnetically recorded on a magnetic recording medium by a recording magnetic field generated by the determined magnetization of the second ferromagnetic layer. A first ferromagnetic layer having a magnetization substantially fixed in a first direction;
A third ferromagnetic layer having a magnetization substantially fixed in a second direction opposite to the first direction;
A second ferromagnetic layer provided between the first ferromagnetic layer and the third ferromagnetic layer and having a variable direction of magnetization;
A first intermediate layer provided between the first ferromagnetic layer and the second ferromagnetic layer;
A second intermediate layer provided between the second ferromagnetic layer and the third ferromagnetic layer;
With
A current is caused to flow between the first and third ferromagnetic layers to cause spin-polarized electrons to act on the second ferromagnetic layer to change the direction of magnetization of the second ferromagnetic layer. Determine the direction according to the direction,
A magnetic head characterized in that information can be recorded by determining the magnetization of the magnetic recording medium by flowing the spin-polarized electrons from the second ferromagnetic layer to the magnetic recording medium. When an electron current flows from the first ferromagnetic layer to the third ferromagnetic layer via the second ferromagnetic layer, the electron current of the second ferromagnetic layer The direction of the magnetization is the first direction,
When an electron current flows from the third ferromagnetic layer to the first ferromagnetic layer via the second ferromagnetic layer, the electron current of the second ferromagnetic layer The magnetic head according to claim 4, wherein the direction of magnetization is the second direction. 7. The method according to claim 1, wherein the magnetization of the second ferromagnetic layer is oriented in a direction substantially orthogonal to the first direction when the current is not flowing. 3. The magnetic head according to claim 1. A first ferromagnetic layer having a magnetization substantially fixed in a first direction;
A second ferromagnetic layer whose magnetization direction is variable;
A first intermediate layer provided between the first ferromagnetic layer and the second ferromagnetic layer;
With
Allowing an electron current to flow from the magnetic recording medium into the second ferromagnetic layer so that the magnetization of the second ferromagnetic layer has a direction corresponding to a spin-polarized state of the electron current;
Between the first and second ferromagnetic layers determined according to a relative relationship between the direction of the magnetization of the first ferromagnetic material and the direction of the magnetization of the second ferromagnetic material. A magnetic head characterized in that information recorded on the magnetic recording medium can be read by detecting a change in resistance. 9. The device according to claim 8, wherein the first intermediate layer is made of an insulator having fine holes, and the first and second ferromagnetic layers are connected through the fine holes. Magnetic head. 10. The magnetic head according to claim 1, wherein the magnetization direction of the first ferromagnetic layer is fixed by an antiferromagnetic layer provided adjacent to the first ferromagnetic layer. 7. The magnetic recording medium according to claim 4, wherein at least one of said first and third ferromagnetic layers has its magnetization direction fixed by an antiferromagnetic layer provided adjacently. The magnetic head according to any one of the above. A magnetic head according to any one of claims 1 to 7,
A magnetic recording apparatus wherein information can be magnetically recorded on a magnetic recording medium. A magnetic head according to claim 8 or 9,
A magnetic recording device wherein information magnetically recorded on a magnetic recording medium can be reproduced.

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