We study spin-transfer-torque (STT) switching of a cross-shaped ferromagnet with unequal branches as the free layer in a magnetic tunnel junction using micromagnetic simulations. The free layer in the magnetic tunnel junction is thus designed to have four stable energy states using shape anisotropy. Switching shows distinct regions with increasing current density. Stability of the states against thermal fluctuations is considered, and the validity of the results for different dimensions and material parameters of the free layer ferromagnet is investigated. The results could be useful for a multi-bit STT-based memory.
Micromagnetic study of spin-transfer-torque switching of a ferromagnetic cross towards multi-state spin-transfer-torque based random access memory
Urmimala Roy, Tanmoy Pramanik, Maxim Tsoi, Leonard F. Register, Sanjay K. Banerjee; Micromagnetic study of spin-transfer-torque switching of a ferromagnetic cross towards multi-state spin-transfer-torque based random access memory. J. Appl. Phys. 14 June 2013; 113 (22): 223904. https://doi.org/10.1063/1.4811230
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