Simulation and Stability Analysis of Current and Transverse Field Effects on Spin Transfer Noise

The spin transfer modified Landau-Lifshitz-Gilbert equation is used to model a permalloy bar with configurations for current, transverse field, and magnetizations resembling those of a read head. The trends of noise power and noise peak frequency against sensing currents and transverse fields with different polarities are calculated and analyzed by symmetry and asymmetry properties, by magnetization dynamics, and by extended linear stability analysis that is applicable to shape anisotropy. With the linear stability analysis, it is found that smaller track width (with aspect ratio fixed) has larger field stability and larger current-density stability