Spin-valve type magnetoresistance sensor and thin-film magnetic head
View Patent ↗A method and apparatus of a spin-type magnetoresistance sensor having a free and pinned magnetic layer stacked with a non-magnetic interposed layer are disclosed. Specifically, the spin-valve type magnetoresistance sensor of the present invention is equipped with a free ferromagnetic layer, a pinned ferromagnetic layer, a non-magnetic spacer layer which is sandwiched between the aforementioned ferromagnetic layers, an anti-ferromagnetic layer which is disposed adjacent to the aforementioned pinned ferromagnetic layer and which is used to pin the direction of magnetization of said pinned ferromagnetic layer, a non-magnetic back layer which is disposed adjacent to the aforementioned free ferromagnetic layer and which is stacked on the opposite side the free ferromagnetic layer from the aforementioned nonmagnetic spacer layer, and an electron-reflective layer which is disposed adjacent to the aforementioned back layer and which is stacked on the opposite side of the back layer from the aforementioned free ferromagnetic layer.
1. A spin-valve type magnetoresistive sensor comprising:
a free ferromagnetic layer;
a pinned ferromagnetic layer;
a non-magnetic spacer layer sandwiched between the free ferromagnetic layer and the pinned ferromagnetic layer;
an anti-ferromagnetic layer disposed adjacent to the pinned ferromagnetic layer;
a non-magnetic back layer disposed adjacent to the free ferromagnetic layer on a side of the free ferromagnetic layer opposite the non-magnetic spacer layer; and
an electron-reflective layer disposed adjacent to the back layer on a side of the non-magnetic back layer opposite the free ferromagnetic layer, the electron-reflective layer comprising a tantalum oxide film formed from a tantalum layer having a thickness within a range of approximately 0.5 to 1.75 nm.
2. The sensor of claim 1 , wherein the non-magnetic back layer has a thickness within a range of approximately 0.5 to 1.5 nm.
3. The sensor of claim 1 , wherein the non-magnetic back layer comprises Cu.
4. An apparatus for sensing magnetic flux comprising:
a spin-valve type magnetoresistive sensor having:
a free ferromagnetic layer;
a pinned ferromagnetic layer;
a non-magnetic spacer layer sandwiched between the free ferromagnetic layer and the pinned ferromagnetic layer;
an anti-ferromagnetic layer disposed adjacent to the pinned ferromagnetic layer;
a non-magnetic back layer disposed adjacent to the free ferromagnetic layer on a side of the free ferromagnetic layer opposite the non-magnetic spacer layer; and
an electron-reflective tantalum oxide layer disposed adjacent to the non-magnetic back layer on a side of the non-magnetic back layer opposite the free ferromagnetic layer.
5. A spin-valve magnetoresistive sensor, comprising:
a free magnetic layer;
a pinned magnetic layer;
a nonmagnetic spacer layer disposed between the free magnetic layer and the pinned magnetic layer;
an antiferromagnetic layer adjacent to the pinned magnetic layer, the pinned magnetic layer pinned by the antiferromagnetic layer; and
a non-magnetic back layer disposed adjacent to the free magnetic layer, the free magnetic layer adjoining and being disposed between the non-magnetic back layer and the nonmagnetic spacer layer, the non-magnetic back layer having a thickness within a range of approximately 0.5 to 1.5 nm;
an electron-reflective layer that adjoins the non-magnetic back layer on a side of the non-magnetic back layer opposite the free magnetic layer, wherein the electron-reflective layer comprises a tantalum oxide film.
6. The spin-valve magnetoresistive sensor of claim 5 , wherein the tantalum oxide film is formed from a tantalum layer having a thickness within a range of approximately 0.5 to 1.75 nm.
7. The spin-valve magnetoresistive sensor of claim 5 , wherein the non-magnetic back layer comprises two or more non-magnetic metal layers.