Antiferromagnetically stabilized pseudo spin valve for memory applications
View Patent ↗The invention relates to improving the switching reliability of a magnetic memory cell in a magnetic random access memory (MRAM). Embodiments of the invention add an antiferromagnet to a magnetic memory cell. An antiferromagnetic layer can be formed adjacent to a soft layer in the MRAM on a side of the soft layer that is opposite to a hard layer of the MRAM. One embodiment further includes an additional interlayer of non-antiferromagnetic material between the antiferromagnetic layer and the soft layer.
1. A digital system comprising:
a magnetic random access memory (MRAM) configured to store data in antiferromagnetically stabilized pseudo spin valves (ASPSVs), where an ASPSV further comprises:
a hard layer of ferromagnetic material, where the hard layer is adapted to store data in a magnetic orientation;
a spacer layer of non-ferromagnetic material disposed adjacent the hard layer;
a soft layer of ferromagnetic material disposed adjacent the spacer layer such that the spacer layer is between the hard layer and the soft layer, where the soft layer is adapted to switch magnetic orientation to allow data to be read from the hard layer;
an antiferromagnetic layer disposed on a side of the soft layer that is opposite to the spacer layer; and
an AFM interlayer disposed between the soft layer and the antiferromagnetic layer, where the AFM interlayer is not formed from an antiferromagnetic material.
2. The digital system as defined in claim 1 , wherein the AFM interlayer is about 1 Å to about 5 Å in thickness.
3. The digital system as defined in claim 1 , wherein the AFM interlayer is about a monolayer in thickness.
4. The digital system as defined in claim 1 , wherein the AFM interlayer is less than a monolayer in thickness.
5. The digital system as defined in claim 1 , wherein the antiferromagnetic layer comprises an alloy of manganese.
6. The digital system as defined in claim 1 , wherein the antiferromagnetic layer comprises at least one of nickel oxide (NiO) and nickel cobalt oxide (NiCoO).
7. The digital system as defined in claim 1 , wherein the AFM interlayer comprises iridium (Ir).
8. The digital system as defined in claim 1 , wherein the AFM interlayer comprises at least one of copper (Cu), ruthenium (Ru), chromium (Cr), and aluminum (Al).
9. The digital system as defined in claim 1 , wherein the spacer layer is in direct contact with the hard layer, where the soft layer is in direct contact with the spacer layer, where the AFM interlayer is in direct contact with the soft layer, and where the antiferromagnetic layer is in direct contact with the AFM interlayer.