Large and highly anisotropic magnetocaloric effects in disordered-perovskite RCr_0.5Fe_0.5O₃ single crystals (R = Gd, Er)

We have successfully synthesized the disordered-perovskite RCr_0.5Fe_0.5O₃ (R=Gd, Er) single crystals which crystallize in an orthorhombic Pbnm structure, and investigated anisotropic magnetic and magnetocaloric properties. In GdCr_0.5Fe_0.5O₃, the isotropic nature of large Gd³⁺ moments leads to a tremendously large entropy change of ~50 J/kg K for both ab and c axes. On the other hand, ErCr_0.5Fe_0.5O₃ exhibits a highly anisotropic magnetocaloric effect which results in a rotational entropy variation of ~21 J/kg K at the ordering temperature of Er³⁺ moments, T_Er = 6 K. Our findings suggest the important roles of magnetic anisotropy of rare-earth magnetic ions and enrich fundamental and applied research on magnetic materials in view of distinct magnetic characteristics in disordered perovskites.