Giant magnetocaloric effect in Mn1−x(Ti0.5V0.5)xAs: Experiments and calculations

Abstract

In this paper, we present the giant magnetocaloric effect exhibited by the Mn1−x(Ti0.5V0.5)xAs compound with x=0.1. The ordering temperature decreases from 318K in the case of MnAs (x=0) to 266K in the case of Mn0.9Ti0.05V0.05As (x=0.1). A large magnetic entropy change −ΔSm attributed to a first order magnetic transition has been observed. For Mn0.9Ti0.05V0.05As, the maximum of −ΔSm occurs near TC=266K and is about 30J∕kgK for an applied field change of 2T, a value very close to that (∼31J∕kgK) measured in MnAs. For materials with a first order transition at TC, the observed magnetocaloric effect enhancement can be explained by magnetoelastic effects which are due to structural changes. A model based on the phenomenological approach of Bean and Rodbell [Phys. Rev. 126, 104 (1962)] has been developed in order to describe such a behavior. In this paper we apply this model to describe the giant magnetocaloric effect exhibited by Mn1−x(Ti0.5V0.5)xAs (x=0, 0.1) materials.