Magnetization Behavior of Synthetic Antiferromagnet and Toggle-Magnetoresistance Random Access Memory

摘要

The magnetization behavior of antiferromagnetically coupled ferromagnetic bilayers with a uniaxial anisotropy is investigated analytically, with the aid of numeric calculation. Field trajectories giving a constant angle to the magnetization of one of the two layers, leaving the other as a variable in the in-plane field two-dimensional co-ordinate, and their envelopes are used to understand the magnetization behavior, including switching. These tools provide a good means of optimizing magnetic parameters to maximize the operating field margins of the recently proposed toggle-mode MRAM devices, including the thermal relaxation. Control of the especially low exchange coupling required for performance optimization is identified as a key technical issue, as well as increase of the operating field strength.