Theoretical investigation of the giant magnetocaloric effect in Er0.7Tm0.3Al2

Abstract

This study presents a theoretical investigation of the giant magnetocaloric effect recently reported in the intermetallic compound Er0.7Tm0.3Al2. Our model Hamiltonian includes the crystalline electrical field, exchange, and Zeeman interactions in both Er3+ and Tm3+ sublattices. A remarkable agreement was achieved between the theoretical calculations and experimental data concerning heat capacity, ΔST and ΔTad (magnetocaloric quantities). Additionally, the analysis of magnetic anisotropy and simulations for the rotating magnetocaloric effect in Er0. 7Tm0.3Al2 were performed. The maximum value for the rotating magnetocaloric effect was predicted around the temperature of spin reorientation transition from the <111>-easy to the <001>-hard magnetization directions.