The static and dynamic properties of skyrmions have recently received increased attention due to the potential application of skyrmions as information carriers and for unconventional computing. While the current-driven dynamics has been explored deeply, both theoretically and experimentally, the theory of temperature gradient-induced dynamics - Skyrmion-Caloritronics - is still at its early stages of development. Here, we move the topic forward by identifying the role of entropic torques due to the temperature dependence of magnetic parameters. Our results show that, skyrmions move towards higher temperatures in single-layer ferromagnets with interfacial Dzyaloshinski-Moriya interactions, whereas, in multilayers, they move to lower temperatures. We analytically and numerically demonstrate that the opposite behaviors are due to different scaling relations of the material parameters as well as a non-negligible magnetostatic field gradient in multilayers. We also find a spatially dependent skyrmion Hall angle in multilayers hosting hybrid skyrmions due to variations of the thickness dependent chirality as the skyrmion moves along the temperature gradient.
@article{arxiv.2205.04385,
title = {Temperature gradient-driven magnetic skyrmion motion},
author = {Eleonora Raimondo and Elias Saugar and Joseph Barker and Davi Rodrigues and Anna Giordano and Mario Carpentieri and Wanjun Jiang and Oksana Chubykalo-Fesenko and Riccardo Tomasello and Giovanni Finocchio},
journal= {arXiv preprint arXiv:2205.04385},
year = {2022}
}