In-plane Anisotropy of Magnetic Damping in Epitaxial Cr/Fe Bilayer Possibly Originating from Orbital Dissipation

Abstract

Understanding the magnetic relaxation process in spin-torque devices for practical applications has remained an open challenge. One of the most important parameters that governs the critical current density for current- induced magnetization switching is the relaxation rate, or magnetic damping α. In this work, we report on a study of the dynamic magnetic properties of an epitaxial Cr/Fe bilayer using ferromagnetic resonance (FMR) techniques. Our findings reveal a strong in-plane anisotropy in the effective magnetic damping of our bilayer film, which contrasts with its negligible magneto-crystalline anisotropy. In this presentation, we will discuss the possible orbital-related mechanisms accounting for the damping anisotropy.