Analytical MRAM test
Raphael P. Robertazzi, J. J. Nowak, et al.
IEEE ITC 2014
We examine the consequences of a strongly interface-concentrated perpendicular magnetic anisotropy (PMA) energy in CoFeB thin films currently in wide use in magnetic tunnel junctions (MTJs) for spin-torque-related memory applications. The direct consequence of such an anisotropy energy distribution, in combination with a moderate exchange coupling of the interface moment to the rest of the film, is a phenomenological appearance of a fourth-order anisotropy term as the film is viewed by ferromagnetic resonance. The presence of a fourth-order anisotropy also affects the apparent thermal activation energy of a patterned nanomagnet with such thin films, and it could lead to an apparent increase in the spin-torque switching efficiency as represented by the ratio of the thermal activation energy and the threshold switching current. However, for interface-sensitive quantities such as tunnel magnetoresistance's hard-axis behavior, as well as for spin-torque excitation processes, the specifics of such separation of interface versus film-interior moment rotation could become important.
Raphael P. Robertazzi, J. J. Nowak, et al.
IEEE ITC 2014
G. Hu, C. Safranski, et al.
IEDM 2022
Orchi Hassan, Rafatul Faria, et al.
IEEE Magnetics Letters
Jonathan Z. Sun, Christopher Safranski, et al.
Physical Review B