Anisotropic magnetic properties and giant rotating magnetocaloric effect in double-perovskite Tb2CoMnO6

Abstract

We investigated the anisotropy of the magnetic and magnetocaloric properties of single-crystalline double-perovskite Tb2CoMnO6, which crystallizes in a monoclinic P2(1)/n structure. Due to dissimilar magnetic anisotropy, the ferromagnetic order of the Co2+ and Mn4+ moments emerges along the c axis at T-C = 100 K, and the larger Tb3+ moments align perpendicular to the c axis, below T-Tb = 15 K. The intricate temperature development of the metamagnetism along the c axis results in a large negative change in the magnetic entropy at low temperature. On the other hand, the larger but almost reversible magnetization, perpendicular to the c axis, results in a small and positive entropy change. This highly anisotropic magnetocaloric effect (MCE) leads to a giant rotational MCE, estimated to be 20.8 J/kg K. Our findings, based on the magnetic anisotropy in Tb2CoMnO6, enrich fundamental and applied research on magnetic materials, considering the distinct magnetic characteristics of double perovskites.