Achieving large magnetocaloric effects in Co- and Cr-substituted Heusler alloys: Predictions from first-principles and Monte Carlo studies

Abstract

The magnetocaloric properties of Ni-Co-Mn-Cr-In Heusler alloys have been studied by means of ab initio calculations and Monte Carlo simulations. We discuss the resulting complex spin configurations, the temperature behavior of entropy, as well as the critical temperatures of the phase transitions. The substitution of 5% Co for Ni and 5% Cr for Mn results in a first-order magnetostructural transition from ferromagnetic austenite to antiferromagnetic martensite, which is accompanied by a spin-flip transition upon cooling. As a result, a large magnetization drop and giant inverse magnetocaloric effect can be achieved of $\mathrm{\ensuremath{\Delta}}{T}_{\text{ad}}\ensuremath{\approx}10$ K in a 2 T field across the magnetostructural phase transition.