Magnetic sensor having an aluminum-nitride seed layer for an anti-ferromagnetic layer
View Patent ↗A magnetic sensor is disclosed that is disposed between top and bottom magnetic shield layers, the sensor comprising: a nonferromagnetic layer disposed beneath the top shield layer; a magnetically soft layer disposed beneath the nonferromagnetic layer, the magnetically soft layer having a magnetization that rotates in response to an applied magnetic field; a ferromagnetic pinned layer disposed beneath the magnetically soft layer; an antiferromagnetic layer disposed beneath the ferromagnetic layer; and an aluminum-nitride seed layer disposed between the antiferromagnetic layer and the bottom shield layer. The aluminum-nitride seed layer decreases sense current shunting, increases pinning strength, increases magnetoresistance and/or increases yield.
1. A magnetic sensor that is disposed between top and bottom magnetic shield layers, the sensor comprising:
a nonferromagnetic layer disposed beneath the top shield layer;
a magnetically soft layer disposed beneath the nonferromagnetic layer, the magnetically soft layer having a magnetization that rotates in response to an applied magnetic field;
a ferromagnetic pinned layer disposed beneath the magnetically soft layer;
an antiferromagnetic layer disposed beneath the ferromagnetic layer; and
an aluminum-nitride layer disposed between the antiferromagnetic layer and the bottom shield layer.
2. The sensor of claim 1 , wherein the aluminum-nitride layer has a thickness that is less than one hundred angstroms.
3. The sensor of claim 1 , wherein the aluminum-nitride layer has a thickness that is in a range between five angstroms and thirty angstroms.
4. The sensor of claim 1 , wherein the antiferromagnetic layer contains manganese.
5. The sensor of claim 1 , wherein the antiferromagnetic layer contains a plurality of crystal grains.
6. The sensor of claim 1 , further comprising a layer that contains chromium and is disposed between the aluminum-nitride layer and the antiferromagnetic layer.
7. The sensor of claim 6 , wherein the layer containing chromium also contains a ferromagnetic element.
8. The sensor of claim 6 , wherein the layer containing chromium also contains nickel.
9. The sensor of claim 1 , wherein the aluminum-nitride layer is crystalline.
10. The sensor of claim 1 , wherein the antiferromagnetic layer includes at least five crystal grains within a distance of sixty nanometers.
11. The sensor of claim 1 , wherein the antiferromagnetic layer contains a metal selected from the group consisting of platinum, palladium, iridium and nickel.
12. A magnetic sensor that is disposed between top and bottom magnetic shield layers, the sensor comprising:
a nonferromagnetic layer disposed beneath the top shield layer;
a magnetically soft layer disposed beneath the nonferromagnetic layer, the magnetically soft layer having a magnetization that rotates in response to an applied magnetic field;
a ferromagnetic pinned layer disposed beneath the magnetically soft layer;
an antiferromagnetic layer disposed beneath the ferromagnetic layer, the antiferromagnetic layer containing manganese; and
a seed layer structure disposed between the antiferromagnetic layer and the bottom shield layer, the seed layer structure including an aluminum-nitride layer and a layer containing chromium.
13. The sensor of claim 1 , wherein the antiferromagnetic layer contains a plurality of crystal grains.
14. The sensor of claim 1 , wherein the seed layer structure has a thickness that is less than one hundred angstroms.
15. The sensor of claim 1 , wherein the aluminum-nitride layer has a thickness that is in a range between five angstroms and thirty angstroms.
16. The sensor of claim 1 , wherein the layer containing chromium also contains a ferromagnetic element.
17. The sensor of claim 1 , wherein the layer containing chromium also contains nickel.
18. The sensor of claim 1 , wherein the antiferromagnetic layer contains a metal selected from the group consisting of platinum, palladium, iridium and nickel.
19. The sensor of claim 1 , wherein the antiferromagnetic layer includes at least five crystal grains within a distance of sixty nanometers.
20. A magnetic sensor that is disposed between top and bottom magnetic shield layers, the sensor comprising:
a nonferromagnetic layer disposed beneath the top shield layer;
a magnetically soft layer disposed beneath the nonferromagnetic layer, the magnetically soft layer having a magnetization that rotates in response to an applied magnetic field;
a ferromagnetic pinned layer disposed beneath the magnetically soft layer;
an antiferromagnetic layer disposed beneath the ferromagnetic layer, the antiferromagnetic layer containing a plurality of crystal grains; and
an aluminum-nitride layer disposed between the antiferromagnetic layer and the bottom shield layer, the aluminum-nitride layer having a thickness that is less than one hundred angstroms.
21. The sensor of claim 20 , further comprising a layer that contains chromium and is disposed between the aluminum-nitride layer and the antiferromagnetic layer.
22. The sensor of claim 21 , wherein the layer containing chromium also contains a ferromagnetic element.
23. The sensor of claim 21 , wherein the layer containing chromium also contains nickel.
24. The sensor of claim 20 , wherein the aluminum-nitride layer has a thickness in a range between five angstroms and thirty angstroms.
25. The sensor of claim 20 , wherein the antiferromagnetic layer contains a metal selected from the group consisting of platinum, palladium, iridium and nickel.
26. The sensor of claim 20 , wherein the antiferromagnetic layer contains at least five of the grains within a distance of sixty nanometers.