Magnetic memory cell based on a magnetic tunnel junction (MTJ) with independent storage and read layers
Embodiments of the invention magnetic memory device, comprising: a magnetic tunnel junction (MTJ) which includes a first free layer optimized for reading; and a second free layer separate from the MTJ and optimized for writing.
1. A method for improving a reliability of an MRAM cell comprising
providing a Magnetic Tunnel Junction (MTJ) having a first free layer of rectangular cross-section;
positioning a second free layer adjacent to the first free layer, wherein the second free layer is independent of the first free layer and defines a storage layer to hold data; wherein the second free layer is of non-rectangular cross-section; and
using the first free layer as a read layer to read data held by the second storage layer.
2. The method of claim 1 , further comprising optimizing the first free layer for reading.
3. The method of claim 1 , further comprising optimizing the second free layer is for storage.
4. The method of claim 1 or claim 2 , wherein the optimizing comprises differentiating the first free layer from the second free layer in terms of one or more of shape, thickness, and material.
5. The method of claim l , wherein the second free layer has an ellipsoidal cross section.
6. A magnetic memory cell, comprising:
a magnetic tunnel junction (MTJ) which includes a first free layer optimized for reading; wherein the first free layer of rectangular cross-section; and
a second free layer separate from the MTJ and optimized for writing; wherein the second free layer is of non-rectangular cross-section.
7. The magnetic memory cell of claim 6 , wherein the first and second free layers are different in terms of one or more of material, shape, and thickness.
8. The magnetic memory cell of claim 6 , wherein the first free layer is optimized for reading in that it requires a lower operative switching field than the second free layer.
9. The magnetic memory cell of claim 6 , wherein the second free layer has an ellipsoidal cross section.
10. A magnetic memory array, comprising:
a plurality of magnetic memory cells, each comprising:
a magnetic tunnel junction (MTJ) which includes a first free layer optimized for reading; wherein the first free layer is of rectangular cross-section; and
an second free layer separate from the MTJ and optimized for writing;
wherein the second free layer is of non-rectangular cross-section; and
read and write lines to energize the magnetic memory cells.
11. The magnetic memory array of claim 10 , wherein the first and second free layers are different in terms of one or more of material, shape, and thickness.
12. The magnetic memory array of claim 10 , wherein the first free layer is optimized for reading in that it requires a lower operative switching field than the second free layer.
13. The magnetic memory array of claim 10 , wherein the second free layer has an ellipsoidal cross section.