Giant reversible adiabatic temperature change and isothermal heat transfer of MnAs single crystals studied by direct method in high magnetic fields

Abstract

The magnetocaloric effect (MCE) in single crystals of MnAs compound was studied both experimentally and theoretically. Direct measurement of MCE showed that the adiabatic temperature change (ΔTad) in a magnetic field of 10 T was 15 K. But direct measurement of the quasi-adiabatic heat transfer (ΔQ) of the sample yielded a value of 9500 J/kg in a magnetic field of 10 T. To date, it is the highest experimentally recorded value for ΔQ by direct measurement. Phenomenological considerations that take into account the interaction of magnetic and structural order parameters explain a number of anomalies in the magnetic and magnetocaloric properties of MnAs that were observed during the experiments.