Investigation of the magnetocaloric effect in double distorted perovskites Ca(Cu _3-xMn _x)Mn ₄O ₁₂(1≤x≤2): From standard ferrimagnetism to glassy ferrimagnetism

The double-distorted perovskites Ca(Cu _3-xMn _x)Mn ₄O ₁₂ (x = 1, 1.25, 1.5, and 2) exhibit a paramagnetic-to-ferrimagnetic transition at a temperature decreasing from T _C 280 K for x = 1 down to T _C 163 K for x = 2. In the latter compound a re-entrantlike spin-glass state emerges around T _g 70 K. For each composition the isothermal entropy change ΔS _M was derived from magnetic measurements recorded up to 9 T. The obtained ΔS _M(T) curves exhibit a broad and dissymmetric distribution, leading to high values of refrigerant capacity. The impact of the x value on the magnetic and magnetocaloric properties is addressed in detail, taking into account the various spin interactions present in these compounds.