Abstract

Atomistic spin dynamics (ASD) is a classical formalism similar to molecular dynamics but for the magnetic moments of a material. It plays an important role in understanding experiments in the field of spintronics as many nanoscale and even macroscopic magnetic quantities are difficult to measure. It has long been known that ASD does not reproduce the expected thermodynamics at low temperatures—where low temperature can even mean room temperature! This is due to the classical approximations inherent in the method. Recently we implemented a quantum thermostat which ensures the thermally excited magnons obey quantum statistics, while the magnetic moments themselves remain classical [1]. We have shown that this allows quantitative calculation of thermodynamic properties across a wide temperature range. I will demonstrate that through parameterisation from state of the art first principles calculations, multiscale models can be constructed which agree very well with experiments [2].

[1] J. Barker & G.E.W. Bauer, Phys. Rev. B 100 , 140401 (2019)

[2] J. Barker, D. Pashov & J. Jackson, Elect. Struct. 2, 044002 (2020)