Exchange coupling film and magnetic sensing element including the same
A magnetic sensing element and exchange coupling film is disclosed. The magnetic sensing element has a free magnetic layer, nonmagnetic material layers disposed on the top and bottom of the free magnetic layer, pinned magnetic layers disposed on the top of one nonmagnetic material layer and on the bottom of the other nonmagnetic material layer, and antiferromagnetic layers containing IrMn disposed on the top of one pinned magnetic layer and on the bottom of the other pinned magnetic layer. The magnetization of the free magnetic layer is aligned in a direction orthogonal to the magnetization direction of the pinned magnetic layers. The exchange coupling film is formed by the antiferromagnetic layer and the pinned magnetic layer above the free magnetic layer. At least an interfacial portion of the ferromagnetic layer which is adjacent to the antiferromagnetic layer contains Co 100-x Fe x wherein 30%≦x≦90% in atomic percent.
1. An exchange coupling film comprising:
an antiferromagnetic layer formed on a ferromagnetic layer; the ferromagnetic layer is in direct contact with the antiferromagnetic layer from below the antiferromagnetic layer; and
an exchange coupling field occurring between the two layers to align magnetization of the ferromagnetic layer in a predetermined direction, wherein
the antiferromagnetic layer comprises IrMn with a thickness ranging from 30 to 80 angstroms and has an Ir content ranging from 15 to 30 atomic percent; and
at least an interfacial portion of the ferromagnetic layer which is adjacent to the antiferromagnetic layer comprises Co 100-x Fe x wherein 40%<x≦90% in atomic percent.
2. The exchange coupling film according to claim 1 , wherein at least the interfacial portion of the ferromagnetic layer which is adjacent to the antiferromagnetic layer comprises Co 100-x Fe x wherein 40%<x≦80% in atomic percent.
3. The exchange coupling film according to claim 2 , wherein at least the interfacial portion of the ferromagnetic layer which is adjacent to the antiferromagnetic layer comprises Co 100-x Fe x wherein 40%<x≦60% in atomic percent.
4. The exchange coupling film according to claim 1 , wherein the antiferromagnetic layer has a thickness of 30 to 80 Å.
5. A magnetic sensing element comprising, from the bottom, a free magnetic layer, a nonmagnetic material layer, a pinned magnetic layer, and an antiferromagnetic layer, magnetization of the free magnetic layer being aligned in a direction orthogonal to a magnetization direction of the pinned magnetic layer,
wherein the pinned magnetic layer and the antiferromagnetic layer comprise the exchange coupling film according to claim 1 .
6. The magnetic sensing element according to claim 5 , wherein the free magnetic layer has a multilayer ferrimagnetic structure including a first magnetic layer, a second magnetic layer, and a nonmagnetic intermediate layer disposed therebetween.
7. A magnetic sensing element comprising:
a free magnetic layer;
an upper nonmagnetic material layer disposed on a top side of the free magnetic layer;
a lower nonmagnetic material layer disposed on a bottom side of the free magnetic layer;
an upper pinned magnetic layer disposed on a top side of the upper nonmagnetic material layer;
a lower pinned magnetic layer disposed on a bottom side of the lower nonmagnetic material layer;
an upper antiferromagnetic layer disposed on a top side of the upper pinned magnetic layer; and
a lower antiferromagnetic layer disposed on a bottom side of the lower pinned magnetic layer, wherein magnetization of the free magnetic layer is aligned in a direction orthogonal to a magnetization direction of the upper and lower pinned magnetic layers, and the upper antiferromagnetic layer and the upper pinned magnetic layer include an exchange coupling field occurring between the two layers to align magnetization of the upper pinned magnetic layer in a predetermined direction, and the upper and lower antiferromagnetic layers comprises IrMn with a thickness ranging from 30 to 80 angstroms and has an Ir content ranging from 15 to 30 atomic percent.
8. The magnetic sensing element according to claim 7 , wherein
the lower antiferromagnetic layer comprises IrMn; and
at least an interfacial portion of the lower pinned magnetic layer which is adjacent to the lower antiferromagnetic layer comprises Co 100-x Fe x wherein 10%≦x≦90% in atomic percent.
9. The magnetic sensing element according to claim 8 , wherein
the lower antiferromagnetic layer comprises IrMn; and
at least the interfacial portion of the lower pinned magnetic layer which is adjacent to the lower antiferromagnetic layer comprises Co 100-x Fe x wherein 10%≦x≦30% in atomic percent.
10. The magnetic sensing element according to claim 7 , wherein
the upper pinned magnetic layer has a multilayer ferrimagnetic structure including a first magnetic layer adjacent to the upper antiferromagnetic layer, a second magnetic layer, and a nonmagnetic intermediate layer disposed between the first and second magnetic layers; and
the upper antiferromagnetic layer and the first magnetic layer comprise an exchange coupling film.