MAGNETORESISTANCE ELEMENT EMPLOYING HEUSLER ALLOY AS MAGNETIC LAYER

Abstract

An advantage of the application is to provide a magnetoresistance element capable of increasing a plateau magnetic field Hp1 while maintaining high ΔRA. A magnetic layer 4c1 adjacent to a non-magnetic material layer 5 in a second fixed magnetic layer 4c constituting the fixed magnetic layer 4 is formed of a first Heusler-alloy layer represented by Co2x(Mn(1-z)Fez)xαy (where the element a is any one element of 3B group, 4B group, and 5B group, x and y all are in the unit of at %, 3x+y=100 at %). Additionally, the content y is in the range of 20 to 30 at % and a Fe ratio z in MnFe is in the range of 0.2 to 0.8. Accordingly, the plateau magnetic field Hp1 may increase while maintaining high ΔRA.

Description

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a cross-sectional view of a reproducing head (thin film magnetic head) which is cut in a direction parallel to an opposite surface of a recording media, and the reproducing head includes a CPP single spin-valve thin film element (magnetic detection device)

FIG. 2 is a cross-sectional view of a reproducing head (thin film magnetic head) which is cut in a direction parallel to an opposite surface of a recording media, and the reproducing head includes a CPP dual spin-valve thin film element (magnetic detection device).

FIG. 3 is a schematic view illustrating an M-H curve in a fixed magnetic layer of a spin-valve thin film element.

FIG. 4 is a graph showing a relationship of an Fe ratio z and a plateau magnetic field Hp1 when a magnetic layer adjacent to a non-magnetic material layer constituting a fixed magnetic layer and a free magnetic layer are formed of Co₂(Mn_1-zFe_x)Ge or Co₂(Mn_1-zFe_z)Si.

FIG. 5 is a graph showing a relationship of Fe ratio z and a plateau magnetic field Hp1 when a magnetic layer adjacent to a non-magnetic material layer constituting a fixed magnetic layer and a free magnetic layer are formed of Co₂(Mn_1-zFe_z)Ge or Co₂(Mn_1-zFe_z)Si.

FIG. 6 is a graph showing a relationship of Fe ratio z and a unidirectional exchanged-bias field (Hex*) when a magnetic layer adjacent to a non-magnetic material layer constituting a fixed magnetic layer and a free magnetic layer are formed of Co₂(Mn_1-zFe_z)Ge or Co₂(Mn_1-zFe_z)Si.

FIG. 7 is a graph showing a relationship of Fe ratio z and a magnetostriction λs of a free magnetic layer when a magnetic layer adjacent to a non-magnetic material layer constituting a fixed magnetic layer and the free magnetic layer are formed of Co₂(Mn_1-zFe_z)Ge or Co₂(M_1-zFe_z)Si.

FIG. 8 is a graph showing a relationship of each composition ratio y of Heusler alloys and ΔRA when a magnetic layer adjacent to a non-magnetic material layer constituting a fixed magnetic layer and the free magnetic layer are formed of Co_2xFe_xAl_y, Co_2xFe_xSi_y, or Co_2xFe_xGe_y (in each of the Heusler alloys, 3x plus y equals 100 at %).

FIG. 9 is a graph showing a relationship of a Fe ratio z and ΔRA when a magnetic layer adjacent to a non-magnetic material layer constituting a fixed magnetic layer is formed of Co₂(Mn_1-zFe_z)Ge or Co₂(Mn_1-zFe_z)Si and the free magnetic layer is formed of Co₂MnGe.

FIG. 10 is a graph showing a relationship of a Fe ratio z and a plateau magnetic field Hp1 when a magnetic layer adjacent to a non-magnetic material layer constituting a fixed magnetic layer is formed of Co₂(Mn_1-zFe_z)Ge or Co₂(Mn_1-zFe_z)Si and the free magnetic layer is formed of Co₂MnGe.

FIG. 11 is a graph showing a relationship of a composition ratio w of each Heusler alloy and ΔRA when a magnetic layer adjacent to a non-magnetic material layer constituting a fixed magnetic layer is formed of Heusler alloys represented by Co_2vMn_vGe_w (v and w all are at % and 3v plus w equals 100 at %) and Co_2vFe_vGe_w.

Claims

1. A magnetic detection device, comprising: a fixed magnetic layer having a fixed magnetization; anda free magnetic layer being formed on the fixed magnetic layer with a non-magnetic material layer interposed therebetween and having a magnetization varied by an exterior magnetic field,wherein the fixed magnetic layer is formed of a first Heusler-alloy layer represented in a formula Co2x(Mn(1-z) Fez)xαy (where an element α is an element selected from 3B group, 4B group, and 5B group, x and y are in the unit of at %, and 3x+y=100 at %), andwherein the content y is in the range of about 20 to 30 at % and a Fe ratio z in MnFe is in the range of about 0.2 to 0.8.

2. The magnetic detection device according to claim 1, wherein the element α is Ge, Si, or Al.

3. The magnetic detection device according to claim 1, wherein the first Heusler alloy layer contacts the non-magnetic material layer.

4. The magnetic detection device according to claim 1, wherein the fixed magnetic layer has a laminated ferri-structure including a first fixed magnetic layer, a second fixed magnetic layer, and a non-magnetic intermediate layer interposed therebetween, and wherein the second fixed magnetic layer contacts the non-magnetic material layer and a part of the second fixed magnetic layer is formed of the first Heusler-alloy layer.

5. The magnetic detection device according to claim 1, wherein the free magnetic layer is formed of a second Heusler-alloy layer represented by Co2vMnvGew (where v and w are in the unit of at % and 3v+w=100 at %) and the content w is in the range of about 21 to 27 at %.

6. A method of manufacturing a spin-valve thin film element, the method comprising: forming an under layer, a seed layer, a antiferromagnetic layer, a fixed magnetic layer, a non-magnetic material layer, a free magnetic layer, and a protecting layer on a lower shield; andforming a magnetic layer adjacent to a non-magnetic layer, wherein the magnetic layer is formed of the first Heusler-alloy layer represented in the formula Co2x(Mn(1-z)Fez)xαy (where an element α is a element selected from 3B group, 4B group or 5B group, x and y all are in the unit of at %, and 3x+y=100 at %) The content y is in the range of 20 to 30 at % and a Fe ratio z is in the range of 0.2 to 0.8 in the composition formula.

7. The method of manufacturing a spin-valve thin film element according to claim 6, wherein forming the fixed magnetic layer includes forming a first fixed magnetic layer, a non-magnetic intermediate layer, and a second fixed magnetic layer, and wherein the second fixed magnetic layer has a double-layer structure in which the magnetic layer is disposed adjacent to the non-magnetic intermediate layer and the magnetic layer is adjacent to the non-magnetic material layer.

8. The method of manufacturing a spin-valve thin film element according to claim 6, wherein the second Heusler-alloy layer is represented by Co2vMnvGew (where v and w are at %, and 3v plus w equals 100 at %), and wherein the content w is represented in the composition formula set in the range of about 21 to 27 at %.

9. The method of manufacturing a spin-valve thin film element according to claim 6, further comprising thermally treating the sping-valve thin film element in the magnetic field.

10. The method of manufacturing a spin-valve thin film element according to claim 9, wherein the spin-valve thin film element is thermally treated at 290° C. for approximately 3 to 4 hours.