Magneto-Thermal MRAM

"Magnetoresistive Random Access Memory (MRAM) density is limited by thermal stabilityof the storage elements for 0.1 micron and smaller lithographies. This proposedprogram overcomes the thermal stability limits of MRAM cells through the use ofintrinsically high coupling fields between a ferromagnetic film and an anti-ferromagnetic film, which creates high storage energy, and through the use of bothmagnetic fields and heating for writing selected cells. Currents in the cellproduce both the magnetic field and Joule heating. Either or both the Neeltemperature of the antiferromagnet and/or the Curie point of the ferromagnet must belower than about 300 degrees C for best operation. Materials, modes of operation,and memory architectures will be explored in Phase I. Repeated (to 10 billion)cell switching with switching times faster than 3 ns using the preferred mode ofoperation will be shown during Phase I. Phase II will show operating arrays ofmagneto-thermal cells with 0.05 micron lithography. This technique can extend theultimate density of MRAM by more than a factor of 10, reduce currents (power), andimprove producibility. Very high density nonvolatile memory can be used commercially for "instant on"applications in computing and to replace slow access time hard disk drives,especially where less than 100 GBytes are required. The intrinsic radiation hardnessand rugged nature of this memory make it especially suited for space applic