Micromagnetic modeling with eddy current and current-induced spin torque effect

Abstract

We present a micromagnetic model which incorporates eddy current and spin transfer torque effects due to the passage of a spin-polarized current in the current-perpendicular-to-plane (CPP) geometry. Eddy current effects are modeled by solving Faraday’s and Poisson’s equations self-consistently with the Landau-Lifshitz-Gilbert (LLG) equation, whereas spin transfer torque is modeled by including the Slonczewski spin torque term in the LLG equation. We consider a 50 nm cubic Co element, which forms the free layer of a pseudo-spin-valve structure. With a typical damping parameter of α=0.5, the eddy currents act to accelerate the magnetic reversal process. The spin torque effect can also assist the reversal process but at high current densities exceeding Jext=108A∕cm2 onwards. At these current densities, spin transfer torque also causes a substantial reduction in the coercivity.