Jonathan Chico, Corina Etz, Lars Bergqvist, Olle Eriksson, Jonas Fransson, Anna Delin, Anders Bergman
It has recently been shown that domain walls in ferromagnets can be moved in the presence of thermal gradients. In this work we study the motion of narrow domain walls in low-dimensional systems when subjected to thermal gradients. The system chosen is a monolayer of Fe on W(1 1 0) which is known to exhibit a large anisotropy while having a soft exchange, resulting in a very narrow domain wall. The study is performed by means of atomistic spin dynamics simulations coupled to first-principles calculations. By subjecting the systems to a thermal gradient we observe a temperature dependent movement of the domain wall as well as changes of the spatial magnetization profile of the system. The thermal gradient always makes the domain wall move towards the hotter region of the sample with a velocity proportional to the gradient. The material specific study is complemented by model simulations to discern the interplay between the thermal gradient, magnetic anisotropy and the exchange interaction, and shows that the larger DW velocities are found for materials with low magnetic anisotropy. The relatively slow DW motion of the Fe/W(1 1 0) system is hence primarily caused by its large magnetic anisotropy.
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http://arxiv.org/abs/1308.0986
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