Thermodynamics and Exchange Stiffness of Asymmetrically Sandwiched Ultrathin Ferromagnetic Films with Perpendicular Anisotropy

Abstract

Ultrathin asymmetrically sandwiched ferromagnetic films can support magnetic skyrmions and skyrmion bubbles, which are eyed as functional units for tomorrow's spintronic logic and memory devices. The type of object and its size and mobility are set by intrinsic magnetic parameters, which are largely unknown. The authors demonstrate that the exchange stiffness of ultrathin films can be determined by analysis of the temperature dependence of magnetization. This simple yet robust approach is crucial not only for the experimental community but also for theorists, as it determines domain-wall thickness, the period of a Dzyaloshinskii spiral, and the characteristic magnetic length.