Numerical Fokker-Planck study of stochastic write error slope in spin torque switching

Abstract

This paper analyzes write errors in spin torque switching due to thermal fluctuations in a system with Perpendicular Magnetic Anisotropy (PMA). Prior analytical and numerical methods are summarized, a physics based Fokker-Planck Equation (FPE) chosen for its computational efficiency and broad applicability to all switching regimes. The relation between write error slope and material parameters is discussed in detail to enable better device engineering and optimization. Finally a 2D FPE tool is demonstrated that extends the applicability of FPE to write error in non PMA systems with built-in asymmetry.