Temperature gradient assisted magnetodynamics in a ferromagnetic nanowire

Abstract

The dynamics of the low energy excitations in a ferromagnet is studied in case a temperature gradient is coupled to the local magnetization. Due to the different time scales of changing temperature and magnetization it is argued that only the coupling between the spatially varying part of the temperature field and the magnetization is relevant. Using variational principles the evolution equation for the magnetic system is found which is strongly influenced by the local temperature profile. The system offers damped spin wave excitations where the strength of damping is determined by the magneto-thermal coupling. Applying the model to nanowires it is demonstrated that the energy spectrum is significantly affected by the boundary conditions as well as the initial temperature distribution. In particular, the coupling between temperature and magnetization is expected to be several orders stronger for the open as for the isolated wire.