Calculating the Magnetocaloric Effect in Second-Order-Type Material by Micromagnetic Simulations: A Case Study on Co ₂B

Abstract

We propose a calculation scheme which integrates micromagnetic simulations and the Arrott-Noakes equation for the investigation of the influence of microstructure and magnetocrystalline anisotropy on the magnetocaloric effect (MCE) in second-order magnetic phase transition materials. Using the Arrott-Noakes equation, the micromagnetic simulation results are extrapolated to temperatures above Curie temperature and applied to MCE calculations. With Co₂B as model material, we perform micromagnetic simulations of nanograins with various grain sizes, boundary thickness, and anisotropy. Based on these results, isothermal entropy change and its dependence on microstructural features in Co₂B nanograins are calculated and shown to agree with experiments.

Keywords: Magnetocaloric, Micromagnetic, Arrott-Noakes