Micromagnetic simulation of current-induced magnetization dynamics in a half-Heusler Co1.5Fe1.5Ge alloy spin-valve nanopillar

Abstract

We investigated the magnetization switching by means of a spin-polarized current via spin-transfer torque (STT) in a half-metallic Heusler Co1.5Fe1.5Ge alloy by numerically solving the Landau–Lifshitz–Gilbert–Slonczewski equation including the STT term in a spin-valve nanopillar Co1.5Fe1.5Ge/Ag/Co1.5Fe1.5Ge using micromagnetic simulation. In this work, we use Co1.5Fe1.5Ge film of 2 nm thickness, and then we inject a spin polarization current perpendicular to plane of the multilayers in order to flip the free layer magnetization and therefore get the magnetization switching between the two layers. Half-metallic Heusler Co1.5Fe1.5Ge is characterized by a small Gilbert damping constant α = 0.0025 and a complete spin polarization at the Fermi level. Using these specific parameters, we obtain the magnetization switching between the free layer and the pinned layer with a critical current density of about 106 A/cm2, as well the magnetization switching process of nanopillar are discussed and analyzed. Also, we deeply examine the behavior of magnetization switching dynamic as a function of the current density within a weak external magnetic field which helps to trig switching. Finally, we studied the impact of free layer thickness on magnetization switching dynamic and STT energy in order to immunize further the switching time and the critical current density.