Magnetic sensing element containing half-metallic alloy
A pinned magnetic layer 20 and a free magnetic layer 26 include a magnetic portion 17 and a magnetic sublayer 22 , respectively, each comprising a half-metallic ferromagnetic alloy. Since each of the magnetic portion 17 and magnetic sublayer 22 comprising the half-metallic alloy layer has a larger value β and a larger resistivity ρ compared to the conventional CoFe alloy or the like, the change in resistance (ΔR) can be increased, and the rate of change in resistance (ΔR/R) can be appropriately improved.
1. A magnetic sensing element comprising:
a multilayer film comprising an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic conductive material layer, and a free magnetic layer,
wherein a current flows perpendicular to planes of the individual layers of the multilayer film, and at least one of the pinned magnetic layer and the free magnetic layer comprises a half-metallic ferromagnetic alloy,
wherein the nonmagnetic conductive layer is interposed between the free magnetic layer and the pinned magnetic layer, and is in contact with the free magnetic layer and the pinned magnetic layer,
wherein the pinned magnetic layer and the free magnetic layer has a laminated ferrimagnetic structure including a first magnetic sublayer, a second magnetic sublayer, and an intermediate nonmagnetic sublayer, the first magnetic sublayer is in contact with the nonmagnetic material layer,
wherein the first magnetic sublayer has a triple-layer structure including a central magnetic sublayer and two outer magnetic sublayers, and the central magnetic sublayer comprises the half-metallic ferromagnetic alloy,
wherein the half-metallic ferromagnetic alloy is Co 0.5 Mn 0.25 (Al 100-a Si a ) 0.25 , wherein a is 0 to 100, and
wherein the free magnetic layer and the central magnetic sublayer and the two outer magnetic sublayers of the triple-layer are each composed of a material whose β value is negative, the value β satisfying the relationship ρ⇓/ρ⇑=(1+β)/(1−β), where ρ⇓ is the resistivity to spin-down conduction electrons and ρ⇑ is the resistivity to spin-up conduction electrons.
2. A magnetic sensing element comprising:
a multilayer film comprising an antiferromagnetic layer, a pinned magnetic layer, a nonmagnetic conductive material layer, and a free magnetic layer,
wherein a current flows perpendicular to planes of the individual layers of the multilayer film, and at least one of the pinned magnetic layer and the free magnetic layer comprises a half-metallic ferromagnetic alloy,
wherein the nonmagnetic conductive layer is interposed between the free magnetic layer and the pinned magnetic layer, and is in contact with the free magnetic layer and the pinned magnetic layer,
wherein the pinned magnetic layer and the free magnetic layer has a laminated ferrimagnetic structure including a first magnetic sublayer, a second magnetic sublayer, and an intermediate nonmagnetic sublayer, the first magnetic sublayer is in contact with the nonmagnetic material layer,
wherein the first magnetic sublayer has a triple-layer structure including a central magnetic sublayer and two outer magnetic sublayers, and the central magnetic sublayer comprises the half-metallic ferromagnetic alloy,
wherein the free magnetic layer and the central magnetic sublayer and the two outer magnetic sublayers of the triple-layer are each composed of a material whose β value is negative, the value β satisfying the relationship ρ⇓/ρ⇑=(1+β)/(1−β), where ρ⇓ is the resistivity to spin-down conduction electrons and ρ⇑ is the resistivity to spin-up conduction electrons,
wherein the half-metallic ferromagnetic alloy is one of NiMnSb, PtMnSb, and PdMnSb.
3. A magnetic sensing element according to claim 1 , wherein the second magnetic sublayer comprises a magnetic material selected from the group consisting of CoFe alloys, CoFeNi alloys, NiFe alloys, and Co.
4. A magnetic sensing element according to claim 1 , wherein the outer magnetic sublayers comprise a magnetic material selected from the group consisting of CoFe alloys, CoFeNi alloys, NiFe alloys, and Co.
5. The magnetic sensing element according to claim 2 , wherein the outer magnetic sublayers comprise a magnetic material selected from the group comprising of FeV alloy, NiCr alloy, and FeCr alloy.