  We investigated the anisotropy of the magnetic and magnetocaloric properties
of singlecrystalline double perovskite Tb2CoMnO6, which crystallizes in a
monoclinic P21/n structure. Due to dissimilar magnetic anisotropy, the
ferromagnetic order of the Co2+ and Mn4+ moments emerges along the c-axis at TC
= 100 K, and the larger Tb3+ moments align perpendicular to the c-axis, below
TTb = 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.
