JP2005051251A - Magnetic detection element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic detection element for improving resistance change amount (ΔR) and resistance change rate (ΔR/R), by improving a material and a film structure of a fixing magnetic layer and/or a free magnetic layer in a CPP (current perpendicular to the plane) magnetic detection element. <P>SOLUTION: The fixed magnetic layer 20 and the free magnetic layer 26 form magnetic layers 17 and 22 formed of a ferromagnetic as well as half-metallic alloy layers. The magnetic layers 17 and 22, consisting of the alloy layers having the half-metal property, have a large β value as compared with the conventional CoFe alloy or the like, and since the specific resistance value ρ is large, the resistance change amount ΔR can be made larger than that of the conventional, and the resistance change rate (ΔR/R) can be properly improved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a CPP (current perpendicular to the plane) type magnetic detection element, and more particularly to a magnetic detection element capable of effectively improving the rate of change in resistance (ΔR / R).

  FIG. 8 is a partial cross-sectional view of the structure of a conventional magnetic detection element as seen from the side facing the recording medium.

  Reference numeral 1 denotes a lower electrode, and an antiferromagnetic layer 2 such as PtMn is formed on the lower electrode 1. Further, a pinned magnetic layer 3 made of CoFe or the like is formed on the antiferromagnetic layer 2, a nonmagnetic material layer 4 made of Cu or the like is formed on the pinned magnetic layer 3, and A free magnetic layer 5 made of NiFe or the like is formed on the nonmagnetic material layer 4. As shown in FIG. 8, an upper electrode 6 is formed on the free magnetic layer 5.

  As shown in FIG. 8, the magnetization of the pinned magnetic layer 3 is pinned in the Y direction in the drawing by an exchange anisotropic magnetic field with the antiferromagnetic layer 2.

  The magnetization of the free magnetic layer 5 is aligned in the X direction in the figure by a longitudinal bias magnetic field from a hard bias layer (not shown) formed on both sides of the free magnetic layer 5 in the track width direction (X direction in the figure).

  The magnetic detection element shown in FIG. 8 has a CPP (current perpendicular to the plane) in which a current flowing from the electrodes 1 and 6 flows in a film thickness direction (Y direction in the drawing) through a multilayer film from the antiferromagnetic layer 2 to the free magnetic layer 5. ) Type magnetic detection element.

The CPP type magnetic sensing element is a CIP (current in the plane) type in which a current flowing from an electrode flows in a multilayer film from the antiferromagnetic layer 2 to the free magnetic layer 5 in a direction parallel to the film surface (X direction in the drawing). As compared with the conventional magnetic detection element, the reproduction output can be increased by narrowing the element size, and the CPP type is expected to be able to appropriately cope with the narrowing of the element size accompanying the future increase in recording density.
Japanese National Patent Publication No. 08-504303 Japanese Patent Laid-Open No. 11-135857 JP 2000-106462 A JP 2001-160640 A JP 2001-237471 A

  By the way, as one of the problems in practical use of the CPP type magnetic sensing element for the future higher recording density, there is an improvement in the resistance change rate (ΔR / R). In order to improve the resistance change rate, the resistance change amount (ΔR) must be improved.

It is known that the resistance change amount (ΔR) is proportional to {β ² / (1-β ² )} · ρ _F · t _F. Here, β is a value determined by the material of the ferromagnetic layer (pinned magnetic layer 3 and free magnetic layer 5), and ρ ↓ / ρ ↑ = (1 + β) / (1-β) {where ρ ↓ is , Ρ ↑ is the specific resistance value of the conduction electrons of the down spin among the conduction electrons, and ρ ↑ is the specific resistance value of the conduction electrons of the up spin among the conduction electrons.

Further, ρ _F is a specific resistance value of the ferromagnetic layer (an average value of specific resistance values for conduction electrons of down spin and up spin), and t is a film thickness of the ferromagnetic layer.

Conventionally, a CoFe alloy or the like has been used as the ferromagnetic layer. The CoFe alloy had a β value of approximately 0.5 and a specific resistance value ρ _F of approximately 16 μΩ · cm.

  Table 1 of “How predictable is the current perpendicular to plane magnetoresistance? (Invited)” (J. Appl. Phys. 79 (8), 15 April 1996) shows that the β value of Co is 0.38 to 0.54. Ni84Fe16 has a β value of 0.34 to 0.66.

  Further, in graph 4 of “Andreev reflection: A new means to determine the spin polarization of refractive materials” (1999 American Institute of Physics), the polarizabilities P of NiFe, Co, Ni, and Fe are approximately 0.33 to 0.45. It is disclosed that. Here, “polarizability P” correlates with the β value described above, and it is known that the β value (absolute value) increases as the polarizability P increases.

However, in the case of magnetic materials such as CoFe alloy, Co, Ni ₈₄ Fe ₁₆ , NiFe, Ni and Fe, the β value and the polarizability P are not sufficiently large values. Was expected to increase the resistance change rate (ΔR / R) by further increasing the resistance change amount (ΔR).

  Therefore, the present invention is to solve the above-described conventional problems, and in particular, by improving the material and film structure of the magnetic layer, the resistance change amount (ΔR) and the resistance change rate (ΔR / R) are improved. An object of the present invention is to provide a magnetic detection element capable of performing the above-described operation.

The present invention provides a magnetic sensing element provided with a multilayer film having an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic material layer, and a free magnetic layer, and a current flows in a direction perpendicular to the film surface of each layer of the multilayer film.
At least one of the pinned magnetic layer and the free magnetic layer is formed to have a ferromagnetic and half-metal alloy layer.

  In the present invention, the absolute value of β value of the ferromagnetic and half-metal alloy layer is preferably 0.7 or more.

  Here, β is a value determined by the material of the ferromagnetic layer, and ρ ↓ / ρ ↑ = (1 + β) / (1-β) {where ρ ↓ is a conduction electron of a down spin among conduction electrons. It is a specific resistance value, and ρ ↑ is a specific resistance value for conduction electrons of upspin among conduction electrons.

  The present invention is a CPP type magnetic detection element, and a sense current flows in a direction perpendicular to the film surface of each layer of the multilayer film.

  The present invention is characterized in that at least one of the pinned magnetic layer and the free magnetic layer is formed to have a ferromagnetic and half-metal alloy layer. “Half-metal” means that the conduction electron of one spin behaves like a metal and the conduction electron of the other spin behaves like an insulator in a ferromagnet or antiferromagnet. To do.

  Conventionally, a magnetic material such as a CoFe alloy used for a ferromagnetic layer has a metallic property, but an alloy layer having a half-metallic property has a β value or Since the polarizability P is large (specifically, the β value (absolute value) is 0.7 or more or the polarizability P (absolute value) is 0.5 or more) and the specific resistance value ρ is also large, the fixed magnetic layer In addition, by including the ferromagnetic and half-metal alloy layer in the free magnetic layer, the resistance change amount ΔR can be increased as compared with the conventional case, and the resistance change rate (ΔR / R) is appropriately improved. It becomes possible.

  The reason (mechanism) that the amount of change in resistance (ΔR) increases as the β value increases is that the specific resistance value (ρ ↓) of one spin with respect to conduction electrons increases as the β value increases. The specific resistance value (ρ ↑) of the other spin with respect to the conduction electron is reduced, that is, the conduction electron of the one spin becomes difficult to flow through the ferromagnetic layer or shut out, and the average of the conduction electrons of the down spin is reduced. While the free path is shortened (shows insulating behavior), the conduction electrons of the other spin tend to flow in the ferromagnetic layer, and the mean free path of the conduction electrons of the other spin is extended (shows metallic behavior) This is thought to be because the mean free path difference between the up-spin conduction electrons and the down-spin conduction electrons is increased.

  The reason (mechanism) that the resistance change amount (ΔR) is increased by increasing the polarizability P is that, when the polarizability P is increased, one of the spins has a higher density of states in the vicinity of Fermi energy (= more number). On the other hand, the other spin has a low density of states in the vicinity of Fermi energy (= the number is small), which increases the mean free path difference between the up-spin conduction electrons and the down-spin conduction electrons, thereby increasing resistance. This is probably because the amount of change (ΔR) has increased.

  Such an action is called spin polarization, and the magnitude of the spin polarization changes depending on the relative magnetization direction relationship between the free magnetic layer 26 and the pinned magnetic layer 20.

  In the present invention, the Curie temperature Tc of the ferromagnetic and half-metal alloy layer is preferably 200 ° C. or higher.

In the present invention, the alloy layer is preferably formed of La _0.7 Sr _0.3 MnO ₃ , CrO ₂ , or Fe ₃ O ₄ .

  In the present invention, the pinned magnetic layer and / or the free magnetic layer has a laminated structure of two or more magnetic layers, and the magnetic layers other than the magnetic layer in contact with the nonmagnetic conductive material layer are included in the magnetic layers. A ferromagnetic and half-metal alloy layer is preferably formed. When the alloy layer has a composition containing a large amount of Mn, the nonmagnetic conductive material layer and this Mn are likely to diffuse, and the diffused Mn shortens the spin diffusion distance and the mean free path of up-spin conduction electrons. Therefore, it is considered that the resistance change amount (ΔR) and the resistance change rate (ΔR / R) may be reduced. Therefore, when the ferromagnetic and half-metal alloy layer has a composition containing a large amount of Mn, it is necessary to form the alloy layer at a position away from the nonmagnetic conductive material layer. It is considered preferable for improving the rate (ΔR / R).

  In the present invention, it is preferable that the magnetic layers other than the magnetic layer on which the ferromagnetic and half-metal alloy layer is formed are formed of any one of a magnetic material of CoFe alloy, CoFeNi alloy, NiFe alloy, or Co.

  In the present invention, the pinned magnetic layer and / or free magnetic layer has a three-layer structure of magnetic layers, and among these three layers, a ferromagnetic and half-metal alloy layer is formed in the middle magnetic layer. Is preferred. By separating the nonmagnetic conductive material layer and the alloy layer in this manner, diffusion between the nonmagnetic conductive material layer and the spin diffusion distance and mean free path of conduction electrons are prolonged as described above. It is possible to expect the effect that the exchange coupling magnetic field generated between the pinned magnetic layer and the antiferromagnetic layer can be increased by separating the alloy layer from the antiferromagnetic layer.

  In the present invention, in such a case, the magnetic layer other than the middle magnetic layer is preferably formed of a magnetic material of any one of CoFe alloy, CoFeNi alloy, NiFe alloy, and Co.

  In the present invention, the pinned magnetic layer and / or the free magnetic layer has a laminated ferrimagnetic structure in which a nonmagnetic intermediate layer is interposed between the first magnetic layer and the second magnetic layer, and at least the nonmagnetic conductive material of the magnetic layer. The first magnetic layer on the side in contact with the layer is preferably formed of a multilayer structure having the ferromagnetic and half-metal alloy layer described above or a single-layer structure of the ferromagnetic and half-metal alloy layer. .

  According to the present invention described in detail above, at least one of the fixed magnetic layer and the free magnetic layer is formed to have a ferromagnetic and half-metal alloy layer.

  Conventionally, magnetic materials such as CoFe alloys used for magnetic layers have metallic properties. However, by using an alloy layer having half-metallic properties, the β value increases and Since the resistance value ρ is also increased, the resistance change amount ΔR can be increased as compared with the conventional case, and the resistance change rate (ΔR / R) can be appropriately improved.

  In the present invention, the resistance change ΔR can be increased more effectively by optimizing the formation position of the ferromagnetic and half-metal alloy layer included in the pinned magnetic layer and the free magnetic layer. It is possible to appropriately improve the rate of change (ΔR / R).

  FIG. 1 is a partial cross-sectional view of the entire structure of the magnetic detection element according to the first embodiment of the present invention as viewed from the side facing the recording medium. In FIG. 1, only the central portion of the element extending in the X direction is shown broken away.

  The magnetic detection element shown in FIG. 1 is for reproducing a signal recorded on a recording medium. Although not shown, a recording inductive head may be laminated on the magnetic detection element.

The magnetic detection element is formed on a trailing end face of a slider made of, for example, alumina-titanium carbide (Al ₂ O ₃ —TiC). The slider is bonded to an elastically deformable support member made of stainless steel or the like on the side opposite to the surface facing the recording medium to constitute a magnetic head device.

  Reference numeral 10 shown in FIG. 1 is a lower shield layer 10 made of a magnetic material such as a NiFe alloy. In this embodiment, the lower shield layer 10 also serves as a lower electrode.

  A base layer 11 made of a nonmagnetic material is formed on the upper shield layer 10. The underlayer 11 also serves as a lower gap layer. The underlayer 11 is preferably formed of at least one of Ta, Hf, Nb, Zr, Ti, Mo, and W. The underlayer 11 is formed with a film thickness of about 50 mm or less, for example.

  Next, a seed layer 12 is formed on the base layer 11. By forming the seed layer 12, the crystal grain size in the direction parallel to the film surface of each layer formed on the seed layer 12 can be increased, and improvement in current-carrying reliability represented by improvement in electromigration resistance, The resistance change rate (ΔR / R) can be improved more appropriately.

  The seed layer 12 is formed of NiFe alloy, NiFeCr alloy, Cr, or the like. The seed layer 12 may not be formed.

  Next, an antiferromagnetic layer 13 is formed on the seed layer 12. The antiferromagnetic layer 13 is an antiferromagnetic material containing an element X (where X is one or more of Pt, Pd, Ir, Rh, Ru, and Os) and Mn. Preferably it is formed. Alternatively, the antiferromagnetic layer 13 includes an element X and an element X ′ (where the element X ′ is Ne, Ar, Kr, Xe, Be, B, C, N, Mg, Al, Si, P, Ti, V, One or two of Cr, Fe, Co, Ni, Cu, Zn, Ga, Ge, Zr, Nb, Mo, Ag, Cd, Sn, Hf, Ta, W, Re, Au, Pb, and rare earth elements It is preferable to be formed of an antiferromagnetic material containing Mn and the above elements.

  These antiferromagnetic materials have excellent corrosion resistance and a high blocking temperature, and can generate a large exchange anisotropic magnetic field at the interface with the pinned magnetic layer 24 described below. The antiferromagnetic layer 13 is preferably formed with a thickness of 80 to 300 mm.

  Next, a pinned magnetic layer 20 is formed on the antiferromagnetic layer 13. In this embodiment, the pinned magnetic layer 20 has a five-layer structure.

  The single magnetic layer 14 and the multilayer 19 of the pinned magnetic layer 20 are magnetic layers, and are nonmagnetic formed of Ru or the like between the second magnetic layer 14 and the first magnetic layer 19. The intermediate layer 15 is interposed, and this configuration makes the magnetization directions of the second magnetic layer 14 and the first magnetic layer 19 antiparallel to each other. This is called a so-called laminated ferri structure. In this specification, in the laminated ferrimagnetic structure, the magnetic layer in contact with the nonmagnetic material layer (nonmagnetic conductive material layer) 21 is called a first magnetic layer, and the other magnetic layer is called a second magnetic layer. The nonmagnetic intermediate layer 15 is formed of one kind of Ru, Rh, Ir, Cr, Re, or Cu or an alloy of two or more kinds thereof. In particular, it is preferably formed of Ru.

  An exchange anisotropic magnetic field is generated between the antiferromagnetic layer 13 and the second magnetic layer 14 of the pinned magnetic layer 20 in contact with the antiferromagnetic layer 13 by heat treatment in a magnetic field, for example, the second magnetic layer. 14 is fixed in the height direction (Y direction shown in the figure), the three magnetic layers constituting the other first magnetic layer 19 are opposite to the height direction (Y direction shown in the figure) due to the RKKY interaction. Magnetized in the opposite direction) and fixed. With this configuration, the magnetization of the pinned magnetic layer 20 can be stabilized, and the exchange anisotropic magnetic field generated at the interface between the pinned magnetic layer 20 and the antiferromagnetic layer 13 can be apparently increased.

  For example, the film thickness of the second magnetic layer 14 is about 10 to 70 mm, and the film thickness of the first magnetic layer 19 composed of multiple layers is about 20 to 80 mm. The film thickness of the nonmagnetic intermediate layer 15 is about 3 to 10 mm.

  The second magnetic layer 14 and the first magnetic layer 19 have different magnetic moments per unit area. The magnetic moment is set as saturation magnetization Ms × film thickness t, and the second magnetic layer 14 and the first magnetic layer 19 are appropriately formed by making the magnetic moments of the second magnetic layer 14 and the first magnetic layer 19 different. A laminated ferri structure is possible.

  A nonmagnetic material layer (nonmagnetic conductive material layer) 21 is formed on the fixed first magnetic layer 19. The nonmagnetic material layer 21 is formed of a conductive material having a low electrical resistance, such as Cu. The nonmagnetic material layer 21 is formed with a film thickness of about 25 mm, for example.

  Next, a free magnetic layer 26 is formed on the nonmagnetic material layer 21. In this embodiment, the free magnetic layer 26 is formed of a three-layer structure of magnetic layers. The total thickness of the free magnetic layer 26 is preferably about 20 to 200 mm.

  A protective layer 25 made of a nonmagnetic material is formed on the free magnetic layer 26. The protective layer 25 also serves as an upper gap layer. The protective layer 25 is preferably formed of at least one of Ta, Hf, Nb, Zr, Ti, Mo, and W. The protective layer 25 is formed with a film thickness of about 50 mm or less, for example.

As shown in FIG. 1, the lower shield layer 10 is formed to extend longer in the track width direction (X direction in the drawing) than the multilayer film from the base layer 11 to the protective layer 25. An insulating layer 40 made of an insulating material such as Al ₂ O ₃ or SiO ₂ is formed on the lower shield layer 10 extending on both sides of the multilayer film in the track width direction (X direction in the drawing). ing. In this embodiment, the upper surface of the insulating layer 40 is formed below the lower surface of the free magnetic layer 26, and the hard bias layer 27 formed of a CoPtCr alloy or the like formed on the insulating layer 40 is used as the free magnetic layer. The layer 26 is magnetically connected to both end faces of the layer 26. The hard bias layer 27 may be at least partially magnetically connected to both end faces of the free magnetic layer 26. When a longitudinal bias magnetic field from the hard bias layer 27 flows into the free magnetic layer 26, the magnetization of the free magnetic layer 26 is made into a single domain in a direction parallel to the track width direction (X direction in the drawing). Unlike the magnetization state of the pinned magnetic layer 20, the magnetization state of the free magnetic layer 26 is weakly single-domained to such an extent that magnetization can be reversed with respect to an external magnetic field.

An insulating layer 28 made of an insulating material such as Al ₂ O ₃ or SiO ₂ is formed on the hard bias layer 27. Thus, the upper and lower sides of the hard bias layer 27 are surrounded by the insulating layers 40 and 28.

  As shown in FIG. 1, the upper surface of the protective layer 25 and the upper surface of the insulating layer 28 are substantially coplanar, and a magnetic layer such as a NiFe alloy is formed on the protective layer 25 to the insulating layer 28. An upper shield layer 29 made of a material is formed. The upper shield layer 29 also serves as an upper electrode of the magnetic detection element.

  In the embodiment shown in FIG. 1, since the lower shield layer 10 and the upper shield layer 29 function not only as a shield function but also as an electrode, the gap length Gl is the same as the film thickness from the base layer 11 to the protective layer 25. And the length dimension of the gap length Gl can be shortened.

  In the embodiment shown in FIG. 1, shield layers 10 and 29 that also serve as electrodes are formed above and below the multilayer film from the base layer 11 to the protective layer 25, and the current flowing between the shield layers 10 and 29 is Is a CPP (current perpendicular to the plane) type that flows in the film thickness direction (Z direction in the figure). Since the upper and lower sides of the hard bias layer 27 are surrounded by the insulating layers 40 and 28, the current flows through the multilayer film appropriately without being divided into the hard bias layer 27, thereby improving the reproduction output. It is possible.

  In this magnetic detection element, the traveling direction of a recording medium such as a hard disk is the Z direction. When a leakage magnetic field from the recording medium is applied in the Y direction, the magnetization of the free magnetic layer 26 starts from a direction parallel to the X direction in the figure. It changes in the direction. The electrical resistance changes depending on the relationship between the fluctuation of the magnetization direction in the free magnetic layer 26 and the fixed magnetization direction of the first magnetic layer 19 of the fixed magnetic layer 20 (this is referred to as magnetoresistance effect). A leakage magnetic field from the recording medium is detected by a voltage change based on the value change.

  A characteristic part of the magnetic detection element shown in FIG. 1 will be described below. In the embodiment shown in FIG. 1, the first magnetic layer 19 of the pinned magnetic layer 20 on the side in contact with the nonmagnetic material layer 21 has a three-layer structure of magnetic layers. Since the first magnetic layer 19 is a layer that actually contributes to the magnetoresistive effect, the resistance change amount (ΔR) and the resistance change (ΔR) higher than those of the prior art can be obtained by making the first magnetic layer 19 particularly as follows. It becomes possible to obtain the rate of change in resistance (ΔR / R).

  Of the three magnetic layers constituting the first magnetic layer 19, the middle magnetic layer 17 is a ferromagnetic and half-metal alloy layer. The necessity of being “ferromagnetic” is because the layer in which this alloy is used forms part of the first magnetic layer 19 and the magnetization needs to be appropriately pinned in the height direction (Y direction in the figure). is there. Here, “Half-metal” means that in one of the ferromagnetic and antiferromagnetic materials, the conduction electron of one spin behaves like a metal and the conduction electron of the other spin is like an insulator. To behave.

The resistance change amount (ΔR) is proportional to {β ² / (1-β ² )} · ρ _F · t _F. Here, β is a value that varies depending on the material of the magnetic layer 17 (note that β is a value within a range larger than −1 and smaller than 1), and the larger the β value, the larger the resistance change amount (ΔR). . The β value of the ferromagnetic and half-metal alloy is larger than that of the CoFe alloy and NiFe alloy conventionally used as the ferromagnetic layer, and thus has a “half-metal” property. In the present invention, a ferromagnetic alloy having a β value (absolute value) of 0.7 or more or a polarizability P (absolute value) described later of 0.5 or more is defined as “half-metal”.

  The β value has the following relationship: ρ ↓ (specific resistance value for downspin conduction electrons) / ρ ↑ (specific resistance value for upspin conduction electrons) = (1 + β) / (1−β). That is, an increase in β value means that ρ ↓ is increased and ρ ↑ is decreased.

  Therefore, as the β value increases, the specific resistance value (ρ ↓) for down-spin conduction electrons increases. Therefore, the down-spin conduction electrons hardly flow or are shut out in the ferromagnetic layer, and the down-spin conduction electrons. On the other hand, the resistivity of the up-spin conduction electrons (ρ ↑) is small, so the up-spin conduction electrons are more likely to flow through the ferromagnetic layer. It is considered that the mean free path of the up-spin conduction electrons is extended (shows a metallic behavior), and the difference in mean free path between the up-spin conduction electrons and the down-spin conduction electrons is increased. Such an action is called spin polarization, and a ferromagnetic and half-metal alloy having a high β value, specifically, a β value (absolute value) of 0.7 or more has a strong spin polarization. Working, the mean free path difference becomes even larger.

  The resistance change amount (ΔR) and the resistance change rate (ΔR / R) are positively correlated with the mean free path difference between the up-spin and down-spin conduction electrons. The amount of change in resistance (ΔR) and rate of change in resistance (ΔR / R) are increased by increasing the mean free path difference between the up-spin conduction electrons and the down-spin conduction electrons due to the use of a half-metal alloy. This makes it possible to manufacture a magnetic detection element that can appropriately cope with an increase in recording density.

  Whether or not it has a “half-metal” property can be determined by the magnitude of the polarizability P in addition to the β value described above. The polarizability P correlates with the β value, and it is known that the β value (absolute value) increases when the polarizability P increases.

  Since the magnitude of the polarizability P is proportional to the resistance change amount (ΔR), the resistance change amount (ΔR) can be increased as the polarizability P increases. The polarizability P is expressed by P = (N ↑ −N ↓) / (N ↑ + N ↓) (where P is −1 ≦ P ≦ 1), where N ↑ is the upspin in the vicinity of Fermi energy. The number of conduction electrons, N ↓ is the number of down-spin conduction electrons near the Fermi energy, and the conduction electrons near the Fermi energy actually contribute to conduction.

  According to the above relational expression, N ↑ increases {that is, the density of states in the vicinity of Fermi energy increases (= the number increases)} and N ↓ decreases {that is, the density of states in the vicinity of Fermi energy decreases (= The smaller the number), the higher the polarizability P, and the larger the resistance change (ΔR).

  The fact that N ↑ becomes larger and N ↓ becomes smaller means that conduction electrons due to upspin flow easily in the ferromagnetic layer, and the mean free path of conduction electrons due to upspin is extended, while conduction electrons due to downspin are reduced. It means that the mean free path of the down-spin conduction electrons is shortened due to difficulty in flowing or being shut out, and thus the difference in the mean free path of the up-spin conduction electrons and the down-spin conduction electrons is increased. It is considered that the resistance change amount (ΔR) increases.

  Therefore, it is preferable to use a ferromagnetic and half-metal alloy having a large polarizability P as the magnetic layer 17. Specifically, the polarizability P (absolute value) is preferably 0.5 or more. In the present invention, it is assumed that the ferromagnetic material having the polarizability P (absolute value) of 0.5 or more has a “half-metal” property.

  The magnitude of the spin polarization varies depending on the relative magnetization direction relationship between the free magnetic layer 26 and the pinned magnetic layer 20.

Further, since the ferromagnetic and half-metal alloy layer has a larger specific resistance value (ρ _F ) than that of the CoFe alloy or the like, the magnetic layer 17 in the middle of the first magnetic layer 19 is made of a ferromagnetic and half-metal alloy. By using a layer, the resistance change amount (ΔR) and the resistance change rate (ΔR / R) can be improved. The “specific resistance value (ρ _F )” referred to here is an average value of the specific resistance value for up-spin conduction electrons and the specific resistance value for down-spin conduction electrons.

The material used for the magnetic layer 17 is preferably a ferromagnetic and half-metal alloy as described above, and the Curie temperature (Tc) is preferably 200 ° C. or higher. If the Curie temperature (Tc) is lower than 200 ° C., it cannot be actually used as a device due to the use environment temperature or the like. The specific resistance ρ _F is preferably 50 μΩ · cm or more. As a result, the resistance change amount (ΔR) and the resistance change rate (ΔR / R) can be improved more appropriately than in the case where a CoFe alloy or the like is conventionally used as the magnetic layer. In the present invention, the rate of change in resistance (ΔR / R) is preferably 30% or more.

  Examples of the material of the ferromagnetic and half-metal alloy layer include the following materials (1) to (3).

(1) The composition formula is X ₂ YZ (where X is one element selected from Group IIIA to Group IIB of the periodic table, Y is Mn, Z is Al, Si, Ga, Ge, In, Sn) , Tl, Pb, Sb, or one or more elements selected from Hesler alloy.

The crystal structure of this Heusler alloy is the L2 structure. Specific examples of the material include Co ₂ MnZ (Z is one or more elements selected from Al, Si, Ga, Ge, and Sn).

Specific examples of Heusler alloys containing two or more elements Z include Co _0.5 Mn _0.25 (Al _100-a Si _a ) _0.25 (where a is 0 to 100).

(2) The composition formula is XYZ (where X is one element selected from IIIA group to IIB group of the periodic table, Y is Mn, Z is Al, Si, Ga, Ge, In, Sn, Tl) Heusler alloy represented by one or more elements selected from Pb, Sb).

The crystal structure of this Heusler alloy is C1 ₂ structure. Specific examples of the material include NiMnSb, PtMnSb, PdMnSb, and PtMnSn.

  Specific polarizabilities P of these materials will be described. Graph 4 of “Andreev reflection: A new means to determine the spin polarization of refractive materials” (1999 American Institute of Physics) discloses that the polarization rate P of NiMnSb is 0.55.

  In Table 1 of “New Class of Materials: Half-Metallic Ferromagnets” (1983 The American Physical Society), N (E) ↑ and N (E) ↓ of NiMnSb, PtMnSb, PdMnSb, and PtMnSn obtained by theoretical calculation are shown. When the polarizability P is calculated using this numerical value, the polarizability P of NiMnSb is 1, the polarizability P of PtMnSb is 1, the polarizability P of PdMnSb is 0.51, and the polarizability P of PtMnSn is -0.33. In addition, it is thought that PtMnSn can make polarizability P 0.5 or more by an absolute value by adjusting a composition ratio.

(3) La _0.7 Sr _0.3 MnO ₃ , CrO ₂ , or Fe ₃ O ₄
Note that, in the graph 4 of “Andreev reflection: A new means to determine the spin polarization of refractive materials” (1999 American Institute of Physics), the polarizability P of La _0.7 Sr _0.3 MnO ₃ is 0.55. It is disclosed that the polarizability P of CrO ₂ is 0.9.

The above-mentioned Heusler alloy, La _0.7 Sr _0.3 MnO ₃ , CrO ₂ , and Fe ₃ O ₄ each have a β value (absolute value) of 0.7 or more or a polarizability P (absolute value) of 0. 5 or more has ferromagnetic and half-metallic properties. By forming the magnetic layer 17 with any of these materials, the resistance change amount (ΔR) and the resistance change rate (ΔR / R) can be compared with the conventional one. Can be improved. All of these materials have a Curie temperature (Tc) of 200 ° C. or higher and a specific resistance value (ρ _F ) of 50 μΩ · cm or higher.

  Next, the magnetic layers 16 and 18 formed above and below the magnetic layer 17 are made of a conventionally used magnetic material, specifically, a CoFe alloy, a CoFeNi alloy, a NiFe alloy, or Co. It is preferable.

  First, the magnetic layer 18 formed in contact with the nonmagnetic material layer 21 is formed of a magnetic material such as a CoFe alloy, so that the diffusion of elements between the magnetic layer 18 and the nonmagnetic material layer 21 can be more appropriately prevented. In addition, it is possible to lengthen the spin diffusion distance and mean free path of up-spin conduction electrons, and appropriately improve the resistance change amount (ΔR) and the resistance change rate (ΔR / R).

  For example, when the magnetic layer 18 is the Heusler alloy (1) or (2) described above, Mn contained in the Heusler alloy diffuses and diffuses with the nonmagnetic material layer 21 formed of Cu or the like. Mn shortens the spin diffusion distance and mean free path of up-spin conduction electrons, and may decrease the resistance change amount (ΔR) and the resistance change rate (ΔR / R). Therefore, as shown in FIG. 1, the magnetic layer 17 formed of a ferromagnetic and half-metal alloy is formed at a position away from the nonmagnetic material layer 21, and the magnetic layer 17 and the nonmagnetic material layer 21 are formed. It is considered that the above diffusion can be appropriately prevented by interposing the magnetic layer 18 formed of a CoFe alloy or the like therebetween. The magnetic layer 18 is preferably formed of a CoFe alloy because the above diffusion can be prevented.

  Next, as shown in FIG. 1, a magnetic layer formed of a CoFe alloy or the like between a magnetic layer 17 formed of a ferromagnetic and half-metal alloy layer and a nonmagnetic intermediate layer 15 formed of Ru or the like. It is considered that the antiferromagnetic coupling due to the RKKY interaction generated between the second magnetic layer 14 and the second magnetic layer 14 can be strengthened, so that the magnetization of the first magnetic layer 19 can be appropriately pinned. It becomes possible to do.

  The pinned magnetic layer 20 shown in FIG. 1 has a laminated ferrimagnetic structure in which a nonmagnetic intermediate layer 15 such as Ru is sandwiched between the second magnetic layer 14 and the first magnetic layer 19. In order to strengthen the stopping, it is necessary to strengthen the antiferromagnetic coupling in the RKKY interaction generated between the second magnetic layer 14 and the first magnetic layer 19. In order to strengthen the antiferromagnetic coupling in the RKKY interaction, it is preferable to form the upper and lower magnetic layers 14 and 16 in contact with the nonmagnetic intermediate layer 15 with a magnetic material such as a CoFe alloy. 16 was made of a magnetic material such as a CoFe alloy. The magnetic layer 16 is preferably formed of a CoFe alloy because the antiferromagnetic coupling in the RKKY interaction can be strengthened more appropriately.

  Next, in the embodiment shown in FIG. 1, the free magnetic layer 26 has a three-layer structure of magnetic layers, and the magnetic layer 22 in the middle of the three magnetic layers is a ferromagnetic and half-metal alloy layer. The magnetic layers 23 and 30 formed above and below are preferably made of a magnetic material of any one of a CoFe alloy, a CoFeNi alloy, and Co.

  Similarly to the pinned magnetic layer 20, the free magnetic layer 26 includes a ferromagnetic and half-metal alloy layer, so that the mean free path difference between the up-spin conduction electrons and the down-spin conduction electrons can be increased. The amount of change (ΔR) and the rate of change in resistance (ΔR / R) can be improved, and a magnetic detection element that can appropriately cope with future increases in recording density can be formed.

  Further, by forming the magnetic layer 30 in contact with the nonmagnetic material layer 21 with a magnetic material such as a CoFe alloy, diffusion between the magnetic layer 30 and the nonmagnetic material layer 21 can be appropriately prevented, and upspin conduction electrons can be prevented. The spin diffusion distance and the mean free path can be appropriately extended, and the resistance change amount (ΔR) and the resistance change rate (ΔR / R) can be increased more appropriately. If the magnetic layer 30 is formed of a CoFe alloy, it becomes possible to prevent the above diffusion more appropriately.

  Further, by forming the magnetic layer 23 with a material having a coercive force Hc smaller than that of a ferromagnetic and half-metal alloy, the sensitivity of the free magnetic layer 26 to the recording magnetic field can be improved. More preferably, the magnetic layer 23 is formed of a NiFe alloy.

  The free magnetic layer 26 must reverse the magnetization with high sensitivity to an external magnetic field. This is because otherwise, a magnetic detection element having excellent reproduction characteristics cannot be manufactured. Many of the ferromagnetic and half-metal alloys such as the Heusler alloys (1) to (3) described above have a large coercive force Hc. Specifically, it is 10 Oe (= about 790 (A / m) or more. When the magnetic layer 30 formed in contact with the nonmagnetic material layer 21 is formed of a CoFe alloy, the coercive force of the CoFe alloy is set. Therefore, in order to improve the sensitivity of the free magnetic layer 26 to an external magnetic field, it is preferable to add a magnetic layer having a small coercive force Hc in the free magnetic layer 23. That is, the magnetic layer. The magnetic layer 23 formed of a NiFe alloy has a coercive force Hc smaller than that of a magnetic layer formed of a ferromagnetic and half-metal alloy or a CoFe alloy. By providing the magnetic layer 23 having a small coercive force Hc, it is possible to manufacture a magnetic detection element excellent in reproducing characteristics that can be reversed in magnetization with high sensitivity to an external magnetic field.

  By the way, as shown in FIG. 1, all the magnetic layers constituting the pinned magnetic layer 20 and the free magnetic layer 26 need to be formed of a material in which the sign of the β value and the sign of the P value described above all have the same sign. .

  That is, for example, if the magnetic layers 17 and 22 formed of a ferromagnetic and half-metal alloy layer have a positive β value, the magnetic layers 16, 18, 30 and 23 are similarly positive values. Must be formed of a magnetic material having a β value of A ferromagnetic and half-metal alloy layer having a positive β value and a high β value (specifically 0.7 or more) extends the mean free path of conduction electrons of upspin ( On the other hand, the action (spin polarization) that shortens the mean free path of down-spin conduction electrons (shows insulating behavior) works strongly, and up-spin conduction electrons and down-spin conductions The difference in mean free path of electrons becomes larger than when a metallic material such as a CoFe alloy is used.

  On the other hand, a ferromagnetic and half-metal-like alloy layer having a negative value works to extend the mean free path of down-spin conduction electrons and shorten the mean free path of up-spin conduction electrons. This is also true for the polarizability P.

  Here, the magnetic layers 16, 18, 30, and 23 formed of a CoFe alloy or the like also have the above-described spin polarization, but the β value of these magnetic layers is a positive value. Therefore, if the magnetic layers 17 and 22, which are ferromagnetic and half-metal alloy layers, have a negative β value, the magnetic layers 16, 18, and 30 have a positive β value. 23, the above-mentioned spin polarization is canceled out, and the difference between the mean free path of the up-spin conduction electrons and the average free path of the down-spin conduction electrons cannot be increased appropriately, and the resistance change amount (ΔR) and the rate of change in resistance (ΔR / R) cannot be effectively increased.

  If the β value is negative and the polarizability P is negative, such as PtMnSb, a ferromagnetic material having a negative β value and a polarizability P is selected for the pinned magnetic layer 20 and the free magnetic layer 26 in the same manner. Therefore, the spin polarization is large, and the resistance change amount (ΔR) can be effectively increased. For example, as such a ferromagnetic material, FeV (β value is about −0.11), NiCr (β value is about −0.24 to −0.11), FeCr (β value is about −0.09). and so on.

  Therefore, in the present invention, all the magnetic layers 16, 17, 18, 30, 22, and 23 constituting the pinned magnetic layer 20 and the free magnetic layer 26 are formed of materials having the same sign as the β value, thereby The polarization becomes synergistically strong, and the difference between the mean free path of the up-spin conduction electrons and the down-spin conduction electron can be increased more effectively, and the resistance change (ΔR) and the resistance change rate It is possible to appropriately improve (ΔR / R).

  The same applies to FIG. 2 and subsequent figures in that the materials having the same β value or polarizability P are used in all the magnetic layers.

  FIG. 2 is a partial cross-sectional view of the structure of the magnetic detection element according to the second embodiment of the present invention as viewed from the side facing the recording medium. 2 and the subsequent description focus only on the film structure of the pinned magnetic layer 20 and the free magnetic layer 26, but the structure of the other layers is not different from that of FIG. 1, so please refer to FIG.

  The first magnetic layer 19 of the pinned magnetic layer 20 shown in FIG. 2 has a two-layer structure. Of these, the magnetic layer 17 is a ferromagnetic and half-metal alloy layer, and the magnetic layer 16 is an alloy layer formed of a magnetic material of CoFe alloy, CoFeNi alloy, NiFe alloy, or Co. preferable.

  In the embodiment shown in FIG. 2, the free magnetic layer 26 also has a two-layer structure like the first magnetic layer 19 of the pinned magnetic layer 20, and the magnetic layer 22 is a ferromagnetic and half-metal alloy layer. The magnetic layer 23 is preferably formed of a magnetic material selected from a CoFe alloy, a CoFeNi alloy, a NiFe alloy, or Co.

The ferromagnetic and half-metal alloy layer has a composition formula of X ₂ YZ (where X is one element selected from Group IIIA to Group IIB of the periodic table, Y is Mn, Z is Al, Heusler alloy represented by Si, Ga, Ge, In, Sn, Tl, Pb, or Sb, or a Heusler alloy represented by XYZ (where X is a periodic table) One element selected from Group IIIA to Group IIB, Y is Mn, Z is one or two selected from Al, Si, Ga, Ge, In, Sn, Tl, Pb, Sb It is preferable to be formed of a Heusler alloy represented by the above elements), La _0.7 Sr _0.3 MnO ₃ , CrO ₂ , Fe ₃ O ₄ or the like.

  Since the above-described ferromagnetic and half-metal alloy layer is included in the pinned magnetic layer 20 and the free magnetic layer 26, the mean free path difference between the up-spin conduction electrons and the down-spin conduction electrons can be compared with the conventional one. The resistance change amount (ΔR) and the resistance change rate (ΔR / R) can be improved.

  When the magnetic layers 17 and 22 in contact with the nonmagnetic material layer 21 of the pinned magnetic layer 20 and the free magnetic layer 26 are formed as ferromagnetic and half-metal alloy layers, when the alloy layer contains Mn, Since there is a risk of Mn diffusion between the nonmagnetic material layer 21 and the embodiment shown in FIG. 2, the resistance change amount (ΔR) and the resistance change rate (ΔR) are compared to the embodiment shown in FIG. / R) is likely to be small, but the amount of change in resistance (when the first magnetic layer 19 and the free magnetic layer 26 are made of only a magnetic material such as a CoFe alloy layer or a NiFe alloy layer as in the prior art). It is considered that (ΔR) and the rate of change in resistance (ΔR / R) can be improved.

In the present invention, the ferromagnetic and half-metal alloy layer is preferably formed of Heusler alloy, CrO ₂ , Fe ₃ O _4, or the like, which hardly causes diffusion.

  Further, the above diffusion is largely caused by a heat treatment process performed when an exchange coupling magnetic field is generated between the second magnetic layer 14 and the antiferromagnetic layer 13 constituting the pinned magnetic layer 20, so that, for example, an exchange coupling magnetic field is generated. However, if the heat treatment process is not necessary, or the heat treatment temperature is low, the above diffusion hardly occurs in the first place. In such a case, the ferromagnetic and half-metal alloy layer is not limited by the material. The magnetic layers 17 and 22 made of can be formed.

  FIG. 3 is a partial sectional view of the structure of the magnetic detection element according to the third embodiment of the present invention as viewed from the side facing the recording medium.

  In the embodiment shown in FIG. 3, as in FIG. 2, the first magnetic layer 19 and the free magnetic layer 26 constituting the pinned magnetic layer 20 have a two-layer structure, but the magnetic layer 18 in contact with the nonmagnetic material layer 21 and the magnetic layer The layer 30 is not a ferromagnetic and half-metal alloy layer, but a layer formed of a magnetic material such as a CoFe alloy, a CoFeNi alloy, a NiFe alloy, or Co. The magnetic layers 18 and 30 are preferably formed of a CoFe alloy because diffusion between the nonmagnetic material layers 21 can be more appropriately prevented.

  In the embodiment shown in FIG. 3, the magnetic layer 17 and the magnetic layer 22 separated from the nonmagnetic material layer 21 are ferromagnetic and half-metal alloy layers.

The ferromagnetic and half-metal alloy layer has a composition formula of X ₂ YZ (where X is one element selected from Group IIIA to Group IIB of the periodic table, Y is Mn, Z is Al, Heusler alloy represented by Si, Ga, Ge, In, Sn, Tl, Pb, or Sb, or a Heusler alloy represented by XYZ (where X is a periodic table) One element selected from Group IIIA to Group IIB, Y is Mn, Z is one or two selected from Al, Si, Ga, Ge, In, Sn, Tl, Pb, Sb It is preferable to be formed of a Heusler alloy represented by the above elements), La _0.7 Sr _0.3 MnO ₃ , CrO ₂ , Fe ₃ O ₄ or the like.

  Since the above-described ferromagnetic and half-metal alloy layer is included in the pinned magnetic layer 20 and the free magnetic layer 26, the mean free path difference between the up-spin conduction electrons and the down-spin conduction electrons can be compared with the conventional one. The resistance change amount (ΔR) and the resistance change rate (ΔR / R) can be improved.

  In the embodiment shown in FIG. 3, the magnetic layer 17 in contact with the nonmagnetic intermediate layer 15 in the first magnetic layer 19 constituting the pinned magnetic layer 20 is formed of a ferromagnetic and half-metal alloy layer. Compared with the embodiment of FIG. 1, the coupling magnetic field due to the RKKY interaction generated between the first magnetic layer 19 and the second magnetic layer 14 may be weakened. For example, the thickness of the magnetic layer 17 is reduced (specifically For example, if it is 10 mm or less), the weakening of the coupling magnetic field due to the RKKY interaction can be suppressed, and the magnetization of the first magnetic layer 19 can be appropriately pinned.

  FIG. 4 is a partial cross-sectional view of the magnetic detection element according to the fourth embodiment of the present invention as viewed from the side facing the recording medium.

  In the embodiment shown in FIG. 4, the film configuration of the pinned magnetic layer 20 is the same as the film configuration of the pinned magnetic layer 20 shown in FIG.

  In FIG. 4, the free magnetic layer 26 has a laminated ferrimagnetic structure in which a nonmagnetic intermediate layer 32 such as Ru is interposed between the first magnetic layer 31 and the second magnetic layer 33.

  As shown in FIG. 4, the first magnetic layer 31 constituting the free magnetic layer 26 has a three-layer structure. Among the three layers, the middle magnetic layer 22 is a ferromagnetic and half-metal alloy layer.

The ferromagnetic and half-metal alloy layer has a composition formula of X ₂ YZ (where X is one element selected from Group IIIA to Group IIB of the periodic table, Y is Mn, Z is Al, Heusler alloy represented by Si, Ga, Ge, In, Sn, Tl, Pb, or Sb, or a Heusler alloy represented by XYZ (where X is a periodic table) One element selected from Group IIIA to Group IIB, Y is Mn, Z is one or two selected from Al, Si, Ga, Ge, In, Sn, Tl, Pb, Sb It is preferable to be formed of a Heusler alloy represented by the above elements), La _0.7 Sr _0.3 MnO ₃ , CrO ₂ , Fe ₃ O ₄ or the like.

  The magnetic layers 23 and 30 formed above and below the magnetic layer 22 are preferably formed of any magnetic material of CoFe alloy, CoFeNi alloy, NiFe alloy, and Co. The magnetic layer 30 in contact with the nonmagnetic material layer 21 is more preferably formed of a CoFe alloy among the magnetic materials in order to appropriately prevent diffusion with the nonmagnetic material layer 21.

  The magnetic layer 23 is preferably formed of a material having a small coercive force Hc in order to improve the sensitivity of the free magnetic layer 26 to an external magnetic field, and the magnetic layer 23 is preferably formed of a NiFe alloy. . A CoFe alloy layer is provided between the magnetic layer 23 and the nonmagnetic intermediate layer 32 and / or between the magnetic layer 33 and the nonmagnetic intermediate layer 32 in order to increase the antiferromagnetic coupling due to the RKKY interaction. Also good.

  The free magnetic layer 26 formed of the laminated ferri structure is affected by the longitudinal bias magnetic field from the hard bias layer 27 formed on both sides thereof, and, for example, the three first magnetic layers 31 of the free magnetic layer 26 are formed. When magnetized in the X direction in the figure, the magnetization of the second magnetic layer 33 is caused by the coupling magnetic field generated by the RKKY interaction generated between the first magnetic layer 31 and the second magnetic layer 33. It is magnetized antiparallel to the magnetization direction.

  In the embodiment shown in FIG. 4, the first magnetic layer 19 of the pinned magnetic layer 20 has the magnetic layer 17 made of a ferromagnetic and half-metal alloy layer, and the first magnetic layer 31 of the free magnetic layer 26 has the magnetic layer 17. And a magnetic layer 22 made of a ferromagnetic and half-metal alloy layer, so that the mean free path difference between the up-spin conduction electrons and the down-spin conduction electrons can be made larger than before, and the resistance change amount (ΔR ) And the rate of change in resistance (ΔR / R) can be improved.

  FIG. 5 is a partial cross-sectional view of the structure of the magnetic detection element of the fifth embodiment viewed from the side facing the recording medium.

  In the embodiment shown in FIG. 5, both the pinned magnetic layer 20 and the free magnetic layer 26 are formed not by a laminated ferrimagnetic structure but only by a multilayer structure of magnetic layers. As shown in FIG. 5, the pinned magnetic layer 20 has a three-layer structure of magnetic layers, and the middle magnetic layer 17 is formed of a ferromagnetic and half-metal alloy layer. The magnetic layers 16 and 18 formed above and below the magnetic layer 17 are preferably made of a magnetic material of any one of CoFe alloy, CoFeNi alloy, NiFe alloy, and Co.

  The antiferromagnetic layer 13 and the magnetic layer 17 formed of a ferromagnetic and half-metal alloy layer intervene with the magnetic layer 16 formed of a magnetic material such as a CoFe alloy, whereby the antiferromagnetic layer is formed. It is considered that the exchange coupling magnetic field generated between the layer 13 and the magnetic layer 16 can be increased, and the magnetization of the pinned magnetic layer 20 can be appropriately pinned. The magnetic layer 16 is more preferably formed of a CoFe alloy, which can effectively increase the exchange coupling magnetic field generated between the magnetic layer 16 and the antiferromagnetic layer 13.

  In the embodiment shown in FIG. 5, the free magnetic layer 26 has a two-layer structure of a magnetic layer, the magnetic layer 22 is a ferromagnetic and half-metal alloy layer, while the magnetic layer 23 is a CoFe alloy or CoFeNi alloy. , NiFe alloy, and Co are preferably used.

  The free magnetic layer 26 has a two-layer structure of a magnetic layer, but this may be a three-layer structure of a magnetic layer as shown in FIG. 1, or a two-layer structure as shown in FIG. A film configuration in which a magnetic layer 22 made of a ferromagnetic and half-metal alloy layer and a magnetic layer 30 made of a CoFe alloy or the like is provided between the magnetic layer 22 and the nonmagnetic material layer 21 may be adopted. .

  In the embodiment shown in FIG. 5, the pinned magnetic layer 20 and the free magnetic layer 26 have magnetic layers 17 and 22 made of a ferromagnetic and half-metal alloy layer, so that up-spin conduction electrons and down-spin conductions. The difference in mean free path with electrons can be made larger than before, and the resistance change amount (ΔR) and the resistance change rate (ΔR / R) can be improved.

  FIG. 6 is a partial cross-sectional view of the structure of the magnetic detection element according to the sixth embodiment of the present invention as viewed from the side facing the recording medium.

  In the embodiment shown in FIG. 6, the pinned magnetic layer 20 has a laminated ferrimagnetic structure in which a nonmagnetic intermediate layer 15 made of Ru or the like is interposed between the second magnetic layer 14 and the first magnetic layer 19. The one magnetic layer 19 is composed of a single layer of a ferromagnetic and half-metal alloy layer, and does not have a multilayer structure as shown in FIGS.

  The free magnetic layer 26 shown in FIG. 6 also has a single-layer structure of a ferromagnetic and half-metal alloy layer.

  If the first magnetic layer 19 and the free magnetic layer 26 are a single layer structure of a ferromagnetic and half-metal alloy layer, these layers can be easily formed.

  Further, when the above-described material having a negative β value (for example, PtMnSn) is used for the ferromagnetic and half-metal alloy layer, it has been conventionally used as a magnetic layer, such as a CoFe alloy or a NiFe alloy. Since the β material has a positive β value, the use of these CoFe alloys in combination with a ferromagnetic and half-metal alloy layer with a negative β value cancels the spin polarization. Therefore, a large resistance change amount (ΔR) and resistance change rate (ΔR / R) cannot be obtained, and therefore, a ferromagnetic and half-metal alloy layer having a negative β value should be formed as a single layer. Is preferred. In such a case, it is preferable that the second magnetic layer 14, the first magnetic layer 19, and the free magnetic layer 26, which are magnetic layers, are all formed of a ferromagnetic and half-metal alloy layer having a negative β value.

  FIG. 7 is a partial cross-sectional view of the structure of the magnetic detection element according to the seventh embodiment of the present invention, viewed from the side facing the recording medium.

  In the embodiment shown in FIG. 7, the pinned magnetic layer 20 is not a laminated ferrimagnetic structure, but a single layer structure of a ferromagnetic and half-metal alloy layer. Similarly, the free magnetic layer 26 is not a laminated ferrimagnetic structure but a single layer structure of a ferromagnetic and half-metal alloy layer.

  If the pinned magnetic layer 20 and the free magnetic layer 26 are a single layer structure of a ferromagnetic and half-metal alloy layer, these layers can be easily formed.

  As shown in FIGS. 6 and 7, if the pinned magnetic layer 20 and the free magnetic layer 26 are formed of a ferromagnetic and half-metal alloy layer, the average of the up-spin conduction electrons and the down-spin conduction electrons. The free path difference can be increased compared to the conventional case, and the resistance change amount (ΔR) and the resistance change rate (ΔR / R) can be improved.

  As described above, the present invention relates to a CPP type magnetic sensing element as shown in FIG. 1 to FIG. 7. When used in a (current in the plane) type, that is, a type of magnetic sensing element in which current flows in a direction parallel to the film surface of the multilayer film (X direction in the figure), the resistance change amount (ΔR) and the resistance change rate ( It is considered that almost no increase in ΔR / R) can be expected. The reason is that the ferromagnetic and half-metal alloy layer has a large specific resistance, so that the santros to other layers is large.

  Therefore, when the ferromagnetic and half-metal alloy layer in the present invention is used for a CPP type magnetic sensing element, the resistance change amount (ΔR) and the resistance change amount (ΔR / R) are more effectively increased. be able to.

  In the magnetic detection element shown in FIGS. 1 to 7, both the pinned magnetic layer 20 and the free magnetic layer 26 include a ferromagnetic and half-metal alloy layer. It may be included in at least one of the magnetic layer 20 and the free magnetic layer 26.

  In the embodiment shown in FIGS. 1 to 7, the multilayer structure of the magnetic layer including the ferromagnetic and half-metal alloy layer has a maximum three-layer structure (for example, the first magnetic layer 19 in FIG. 1). Or the free magnetic layer 26), but this may be four or more layers. In such a case, the ferromagnetic and half-metal alloy layer may be formed at any lamination position.

  In the embodiment shown in FIGS. 1 to 7, there is no form in which the free magnetic layer 26 side has a laminated ferrimagnetic structure and the pinned magnetic layer 20 side does not have a laminated ferrimagnetic structure but a single layer structure or a multilayer structure having only a magnetic layer. Of course, such a form may be used.

  When the pinned magnetic layer 20 and the free magnetic layer 26 shown in FIG. 4 have a laminated ferrimagnetic structure, the second magnetic layers 14 and 33 are also ferromagnetic and half-metal alloys like the first magnetic layers 19 and 31. A single-layer structure composed of layers or a multilayer structure including the ferromagnetic and half-metal alloy layer may be used.

  Further, a combination of the laminated structure of the pinned magnetic layer 20 and the laminated structure of the free magnetic layer 26 not shown in FIGS. 1 to 7, for example, the laminated structure of the fixed magnetic layer 20 shown in FIG. 1 and the free magnetic shown in FIG. Needless to say, the magnetic detecting element may be combined with the layered structure of the layer 26.

  In all of the magnetic sensing elements shown in FIGS. 1 to 7, the antiferromagnetic layer 13, the pinned magnetic layer 20, the nonmagnetic material layer 21, and the free magnetic layer 26 are laminated in this order from the bottom. The free magnetic layer 26, the nonmagnetic material layer 21, the pinned magnetic layer 20, and the antiferromagnetic layer 13 may be laminated in this order.

  Further, the magnetic detection element shown in FIGS. 1 to 7 has a structure called a single spin valve thin film element in which a fixed magnetic layer and a free magnetic layer are provided one by one. The present invention can also be applied to a structure called a dual spin valve thin film element including a layer, a pinned magnetic layer, a nonmagnetic material layer, a free magnetic layer, a nonmagnetic material layer, a pinned magnetic layer, and an antiferromagnetic layer.

  The magnetic detection element in the present invention can be used not only for a thin film magnetic head mounted on a hard disk device, but also for a magnetic head for tape, a magnetic sensor, and the like.

The fragmentary sectional view which looked at the magnetic detection element of a 1st embodiment in the present invention from the surface opposite to a recording medium, The fragmentary sectional view which looked at the magnetic sensing element of a 2nd embodiment in the present invention from the opposing surface side to a recording medium, The fragmentary sectional view which looked at the magnetic detection element of 3rd Embodiment in this invention from the opposing surface side with a recording medium, The fragmentary sectional view which looked at the magnetic detection element of 4th Embodiment in this invention from the opposing surface side with a recording medium, The fragmentary sectional view which looked at the magnetic detection element of 5th Embodiment in this invention from the opposing surface side with a recording medium, The fragmentary sectional view which looked at the magnetic detection element of 6th Embodiment in this invention from the opposing surface side with a recording medium, The fragmentary sectional view which looked at the magnetic detection element of 7th Embodiment in this invention from the opposing surface side with a recording medium, Partial sectional view of a conventional magnetic detection element as seen from the side facing the recording medium,

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Lower shield layer 11 Underlayer 12 Seed layer 13 Antiferromagnetic layers 14, 33 Second magnetic layers 15, 32 Nonmagnetic intermediate layers 16, 17, 18, 22, 23, 30 Magnetic layers 19, 31 First magnetic layer 20 Fixed magnetic layer 21 Nonmagnetic material layer 25 Protective layer 26 Free magnetic layer 29 Upper shield layer

Claims (9)

In a magnetic sensing element provided with a multilayer film having an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic conductive material layer and a free magnetic layer, and a current flows in a direction perpendicular to the film surface of each layer of the multilayer film,
At least one of the fixed magnetic layer and the free magnetic layer is formed to have a ferromagnetic and half-metal alloy layer. The magnetic detection element according to claim 1, wherein the absolute value of the β value of the ferromagnetic and half-metal alloy layer is 0.7 or more.
Here, β is a value determined by the material of the ferromagnetic layer, and ρ ↓ / ρ ↑ = (1 + β) / (1-β) {where ρ ↓ is a conduction electron of a down spin among conduction electrons. It is a specific resistance value, and ρ ↑ is a specific resistance value for conduction electrons of up-spin among conduction electrons}.   The magnetic detection element according to claim 1 or 2, wherein the ferromagnetic and half-metal alloy layer has a Curie temperature Tc of 200 ° C or higher. 4. The magnetic detection element according to claim 1, wherein the alloy layer is formed of La _0.7 Sr _0.3 MnO ₃ , CrO ₂ , or Fe ₃ O ₄ .   The pinned magnetic layer and / or free magnetic layer has a laminated structure of two or more magnetic layers, and among these magnetic layers, a magnetic layer other than the magnetic layer in contact with the nonmagnetic conductive material layer is provided with the ferromagnetic and half metal layer. The magnetic detection element according to claim 1, wherein a typical alloy layer is formed.   The magnetic detection element according to claim 5, wherein the magnetic layers other than the magnetic layer on which the ferromagnetic and half-metal alloy layer is formed are formed of any one of a magnetic material of CoFe alloy, CoFeNi alloy, NiFe alloy, or Co. .   5. The fixed magnetic layer and / or the free magnetic layer has a three-layer structure of magnetic layers, and among these three layers, a ferromagnetic and half-metal alloy layer is formed in the middle magnetic layer. Any one of the magnetic detection elements.   8. The magnetic sensing element according to claim 7, wherein the magnetic layers other than the middle magnetic layer are formed of a magnetic material of any one of a CoFe alloy, a CoFeNi alloy, a NiFe alloy, and Co.   The pinned magnetic layer and / or free magnetic layer has a laminated ferrimagnetic structure in which a nonmagnetic intermediate layer is interposed between the first magnetic layer and the second magnetic layer, and at least the magnetic layer on the side in contact with the nonmagnetic conductive material layer The first magnetic layer is formed of a multilayer structure having the ferromagnetic and half-metal alloy layer or a single-layer structure of the ferromagnetic and half-metal alloy layer. Magnetic detection element.

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