Magnetocaloric effect in the layered organic-inorganic hybrid (CH₃NH₃)₂CuCl₄

We present a study of magnetocaloric effect of the quasi-two-dimensional (2D) ferromagnet (CH₃NH₃)₂CuCl₄ in ab plane (easy-plane). From the measurements of magnetic field dependence of magnetization at various temperatures, we have discovered a large magnetic entropy change associated with the ferromagnetic-paramagnetic transition. The heat capacity measurements reveal an abnormal adiabatic change below the Curie temperature T_c~8.9 K, which is caused by the nature of quasi-2D layered crystal structure. These results suggest that perovskite organic-inorganic hybrids with a layered structure are suitable candidates as working substances in magnetic refrigeration technology.