Magnetic disk apparatus
View Patent ↗A magnetic disk apparatus having a highly sensitive reproducing head and a method for manufacturing the magnetic disk apparatus are disclosed. A spin-valve-type multilayer film composed of an antiferromagnetic layer, a ferromagnetic layer, a nonmagnetic layer and a free magnetic layer is used as a magnetoresistive-effect device for the reproducing head. An antiferromagnetic reaction layer is formed between the antiferromagnetic reaction layer and the ferromagnetic layer. The antiferromagnetic reaction layer is formed of a metallic compound containing oxygen.
1. A magnetic disk apparatus comprising:
a magnetoresistive-effect device having a spin-valve type multilayer film comprising:
an antiferromagnetic layer;
an antiferromagnetic reaction layer;
a ferromagnetic layer;
a nonmagnetic layer; and
a free magnetic layer;
wherein the antiferromagnetic reaction layer is located between the antiferromagnetic layer and the ferromagnetic layer, and the antiferromagnetic reaction layer comprises a metallic compound containing oxygen and a metallic compound containing a same metal as in the antiferromagnetic layer.
2. A magnetic disk apparatus according to claim 1 , wherein the magnetoresistive-effect device is capable of operating with a current direction perpendicular to a film surface (CPP mode).
3. The magnetic disk apparatus according to claim 1 , wherein the antiferromagnetic reaction layer contains Mn.
4. The magnetic disk apparatus according to claim 3 , wherein the antiferromagnetic reaction layer contains at least one constituent selected from a group consisting of nitrogen, hydrogen and H.sub.2O.
5. The magnetic disk apparatus according to claim 1 , wherein the antiferromagnetic reaction layer is formed by natural oxidation or plasma oxidation.
6. The magnetic disk apparatus according to claim 1 , wherein the antiferromagnetic layer comprises a Mn-based alloy containing at least one constituent selected from a group consisting of Pt, Ir, Ru and Rh, and a base layer under the antiferromagnetic layer comprises either NiFe or NiFeCr.
7. The magnetic disk apparatus according to claim 1 , wherein the ferromagnetic layer and the free magnetic layer comprise an alloy containing at least one of Fe, Co and Ni, and the nonmagnetic comprises an alloy containing Cu.
8. The magnetic disk apparatus according to claim 1 , wherein the ferromagnetic layer comprises a stacked ferrimagnetic structure constituted by a first ferromagnetic layer, a metallic intermediate layer and a second ferromagnetic layer, and the metallic intermediate layer is formed of an alloy containing at least one constituent selected from a group consisting of Ru, Cu, Rh, Pd, Ag, Ir, Pt and Au.
9. The magnetic disk apparatus according to claim 1 , wherein a film thickness of the antiferromagnetic reaction layer is 0.1 nm to 2.5 nm.