Magnetocaloric Properties Of Mn_3sn_2 From Heat Capacity Measurements

摘要

The heat capacity of the Mn_3Sn_2 compound was measured between 2 and 300 K in magnetic fields up to 7 T. The isothermal magnetic entropy change (ΔS_M) and the adiabatic temperature change (ΔT_(ad)) were calculated from these data. In agreement with previous magnetic measurements, three transitions are detected in the zero-field heat capacity versus temperature curve, two λ-like peaks close to T_(c1) ～ 262 K and T_(c2) ～ 227 K due to ferromagneticlike second-order transitions and a third anomaly at T_t～ 197 K ascribed to the development of a weak antiferromagnetic interaction. The Debye temperature is estimated to be ～303 K from the low-temperature data. The thermal dependences of ΔS_M and ΔT_(ad) present a two-peak response with peak maxima near T_(c1) and T_(c2). For a field variation of 5 T, the values of ΔT_(ad) are found to be ～2.1 and ～1.6 K, respectively. The results are discussed and compared to previously published data concerning other magnetic refrigerants working near room temperature.