L. Savtchenko, et al., US Patent , 6, 545,906 B1 (2003).

1. Materials Research Science and Engineering CenterWilliam H. ButlerUniversity of Alabama-Tuscaloosa,DMR-0213985 Compensated orthogonal anisotropy toggle-MRAMH. Fujiwara, and S. Y. Wang Magnetic Random Access Memory (MRAM) is an emerging memory technology that stores information using the magnetic polarity of a thin ferromagnetic layer. MRAM cells have many potential advantages. They are non-volatile, and can be as fast and dense as DRAM cells. They can be implemented above an active silicon substrate as part of a single chip in the same manner as DRAM cells. One of the most important problems to be solved in making MRAM into a practical commercial device has been the relatively small operating field margin. The original designs for MRAM cells required that every cell be essentially identical in its magnetic properties to avoid errors in writing bits into cells. The recent proposal of toggle-MRAM by Savchenko, et al1, in which the memory element is composed of a synthetic antiferromagnet addresses this problem by providing larger margins for writing. However, toggle-MRAM requires a much stronger magnetic field for its operation compared to the original designs. This severely limits the density of MRAM because the fields must be supplied by current lines. We have designed a new type of toggle-MRAM element, in which the two anisotropy axes (intrinsic and shape) are orthogonally aligned to compensate each other. (See the figure.) With this design one can have both the high field margin of toggle-MRAM and the low write field characteristic of standard MRAM. L. Savtchenko, et al., US Patent, 6, 545,906 B1 (2003). S.-Y. Wang and H. Fujiwara, J. Appl. Phys. Vol. 98, 024510-1-7 (2005).