Large entropy change accompanying two successive magnetic phase transitions in TbMn2Si2 for magnetic refrigeration

Structural and magnetic properties in TbMn2Si2 are studied by variable temperature X-ray diffraction, magnetization, electrical resistivity, and heat capacity measurements. TbMn2Si2 undergoes two successive magnetic transitions at around Tc1 = 50 K and Tc2 = 64 K. Tc1 remains almost constant with increasing magnetic field, but Tc2 shifts significantly to higher temperature. Thus, there are two partially overlapping peaks in the temperature dependence of magnetic entropy change, i.e., −ΔSM (T). The different responses of Tc1 and Tc2 to external magnetic field, and the overlapping of −ΔSM (T) around Tc1 and Tc2 induce a large refrigerant capacity (RC) within a large temperature range. The large reversible magnetocaloric effect (−ΔSM peak = approx. 16 J/kg K for a field change of 0-5 T) and RC (=396 J/kg) indicate that TbMn2Si2 could be a promising candidate for low temperature magnetic refrigeration.