Multi-bit MRAM device with switching nucleation sites
View Patent ↗A magnetic memory cell includes a first magneto-resistive device and a second magneto-resistive device. The first magneto-resistive device has a first sense layer. The second magneto-resistive device is connected in series with the first magneto-resistive device. The second magneto-resistive device has a second sense layer. At least one controlled nucleation site is placed on at least one of the first sense layer and the second sense layer.
1. A magnetic memory cell comprising:
a first magneto-resistive device having a first sense layer; and,
a second magneto-resistive device connected in series with the first magneto-resistive device, the second magneto-resistive device having a second sense layer;
wherein at least one controlled nucleation site is placed on at least one of the first sense layer and the second sense layer.
2. A magnetic memory cell as in claim 1 wherein each of the first sense layer and the second sense layer has at least one controlled nucleation site.
3. A magnetic memory cell as in claim 1 wherein nucleation sites on the first sense layer are different in shape relative to nucleation sites on the second sense layer.
4. A magnetic memory cell as in claim 1 wherein nucleation sites on the first sense layer are different in size relative to nucleation sites on the second sense layer.
5. A magnetic memory cell as in claim 1 wherein nucleation sites on the first sense layer are different in placement relative nucleation sites on the second sense layer.
6. An information storage device composed of a plurality of magnetic memory cells, each cell comprising:
a first magneto-resistive device; and,
a second magneto-resistive device connected in series with the first magneto-resistive device;
wherein the plurality of magnetic memory cells have increased switching predictability resulting from placement of at least one controlled nucleation site on a sense layer of at least one of the first magneto-resistive device and the second magneto-resistive device.
7. An information storage device as in claim 6 wherein a sense layer for each of the first magneto-resistive device and the second magneto-resistive device have at least one controlled nucleation site.
8. An information storage device as in claim 6 wherein nucleation sites on a sense layer of the first magneto-resistive device are different in shape relative to nucleation sites on a sense layer of the second magneto-resistive device.
9. An information storage device as in claim 6 wherein nucleation sites on a sense layer of the first magneto-resistive device are different in location relative to nucleation sites on a sense layer of the second magneto-resistive device.
10. An information storage device as in claim 6 wherein nucleation sites on a sense layer of the first magneto-resistive device are different in size relative to nucleation sites on a sense layer of the second magneto-resistive device.
11. A device comprising:
a magnetic random access memory, the magnetic random access memory comprising a plurality of magnetic memory cell, each magnetic memory cell comprising:
a first magneto-resistive device having a first sense layer, and
a second magneto-resistive device connected in series with the first magneto-resistive device, the second magneto-resistive device having a second sense layer;
wherein at least one controlled nucleation site is placed on at least one of the first sense layer and the second sense layer.
12. A device as in claim 11 wherein the device is a long term data storage device.
13. A device as in claim 11 wherein the device is a solid state hard drive.
14. A device as in claim 11 wherein the device is a digital camera.
15. A device as in claim 11 wherein the device is a processor.
16. A device as in claim 11 wherein the device is a network appliance.