Giant magnetocaloric effect in Ho_(12)Co_7 compound

摘要

Magnetic properties and magnetocaloric effects of HO_(12)Co_7 compound are investigated by magnetization and heat capacity measurement. The HO_(12)Co_7 compound undergoes antiferromagnetic (AFM)-AFM transition at T_1=9K, AFM-ferromagnetic (FM) transition at T_2=17K, and FM-paramagnetic transition at T_c = 30 K, with temperature increasing. There are two peaks on the magnetic entropy change (△S_M) versus temperature curves and the maximal value of -△Sm is found to be 19.2 J/kg K with the refrigerant capacity value of 554.4 J/kg under a field change from 0 to 5 T. The shape of the △SmT curves obtained from heat capacity measurement is in accordance with that from magnetization measurement. The excellent magnetocaloric performance indicates the applicability of Ho_(12)Co_7 as an appropriate candidate for magnetic refrigerant in low temperature ranges.