Reversibility in the inverse magnetocaloric effect in Mn3GaC studied by direct adiabatic temperature-change measurements

Abstract

Thermal-hysteresis affects adversely the reversibility of the magnetocaloric effect around a first order magnetostructural transition. In Mn3GaC, a first order antiferromagnetic-ferromagnetic transition is accompanied by a volume-change and a 5 K thermal-hysteresis. We study the reversibility of the magnetocaloric effect in the transition region by direct adiabatic temperature-change measurements. The magnetic field is cycled between 0 and 3 T, and the temperature-change is observed. We find that the system exhibits a temperature-change of 3.1 K in the virgin state, and all subsequent cycling leads to a 2.8 K warming and cooling when the field is decreased and increased, respectively.