In this article, the effect of thermal fluctuations on switching field at short and long time scales have been investigated by micromagnetic simulation with the Langevin and the time-temperature scaling methods. When the film thickness and/or the aspect ratio are reduced, the switching field decreases substantially owing to the decrease of shape anisotropy and the increase of thermal fluctuation. In the soft magnetic film with a dimension of 0.4μm×0.2μm×1nm, the calculated switching field at a pulse width of 10 ns is 32 Oe, but estimated retention time is less than 1000 s. In such a thermally unstable film, thermally activated switching of magnetization occurs by complex behaviors with creations and annihilations of small and slightly tilted magnetic clusters.
ASJC Scopus subject areas
- Physics and Astronomy(all)