GMR sensors with strongly pinning and pinned layers
View Patent ↗A giant magnetoresistance (GMR) sensor with strongly pinning and pinned layers is described for magnetic recording at ultrahigh densities. The pinning layer is an antiferromagnetic (AFM) iridium-manganese-chromium (Ir—Mn—Cr) film having a Mn content of approximately from 70 to 80 atomic percent and having a Cr content of approximately from 1 to 10 atomic percent. The first pinned layer is preferably a ferromagnetic Co—Fe having an Fe content of approximately from 20 to 80 at % and having high, positive saturation magnetostriction. The second pinned layer is preferably a ferromagnetic Co—Fe having an Fe content of approximately from 0 to 10 atomic percent. The net magnetic moment of the first and second pinned layers is designed to be nearly zero in order to achieve a pinning field of beyond 3,000 Oe.
1. A bottom-type giant magnetoresistance (GMR) sensor comprising:
a nonmagnetic Al—O first seed layer;
a nonmagnetic Ni—Cr—Fe second seed layer deposited on the first seed layer;
a ferromagnetic Ni—Fe third seed layer deposited on the second seed layer;
an antiferromagnetic Ir—Mn—Cr pinning layer deposited on the third seed layer;
a ferromagnetic Co—Fe first pinned layer deposited on the pinning layer;
a nonmagnetic Ru antiparallel (AP) spacer layer deposited on the first pinned layer;
a ferromagnetic Co—Fe second pinned layer deposited on the AP spacer layer;
a nonmagnetic Cu—O GMR spacer layer deposited on the second pinned layer;
a first free layer of ferromagnetic Co—Fe deposited on the GMR spacer layer;
a second free layer of ferromagnetic Ni—Fe deposited on the first free layer; and
a nonmagnetic Ta cap layer deposited above the first and second free layers;
wherein the first pinned layer comprises first and second Co—Fe films, the first Co—Fe film contacting the antiferromagnetic pinning layer and having an Fe content of approximately from 20 to 80 atomic percent, and the second Co—Fe film contacting the AP spacer layer and having an Fe content of approximately from 0 to 10 atomic percent.
2. The GMR sensor of claim 1 wherein the Co—Fe first free layer has an Fe content of approximately from 10 to 20 atomic percent, the Ni—Fe second free layer has an Fe content of approximately from 5-15 atomic percent, and the Co—Fe/Ni—Fe free layers have a nearly zero or negative saturation magnetostriction.
3. The GMR sensor of claim 1 wherein the antiferromagnetic Ir—Mn—Cr pinning layer has a Cr content of approximately from 1 to 10 atomic percent.
4. The GMR sensor of claim 1 wherein the antiferromagnetic Ir—Mn—Cr pinning layer has a Mn content of approximately from 70 to 80 atomic percent.
5. The GMR sensor of claim 1 wherein the first pinned layer has an Fe content of approximately from 20 to 80 atomic percent.
6. The GMR sensor of claim 1 wherein the second pinned layer has an Fe content of approximately from 0 to 10 atomic percent.
7. The GMR sensor of claim 1 wherein a net magnetic moment of the first and second pinned layers is approximately zero.
8. The GMR sensor of claim 1 wherein the first pinned layer has a higher positive saturation magnetostriction than the second pinned layer.