Critical switching current and thermal stability of magnetic tunnel junctions with uncompensated CoFeB/Ru/CoFeB synthetic free layers

The critical switching current and thermal stability parameter are investigated for magnetic tunnel junctions with uncompensated synthetic ferrimagnetic free layers. The parameters are obtained by analyzing the experimental results for the thermally activated magnetization switching probability as functions of both a bias current and an applied magnetic field. The analysis is greatly facilitated by the use of an analytical equation for the applied magnetic field dependence of the energy barrier. A figure of merit given by the ratio of the two parameters differs substantially depending on the direction of the magnetization switching. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4794340]