The study of low-field positive and negative magnetic entropy changes in Ni43Mn46−xCuxSn11 alloys

Abstract

A series of Ni 43 Mn 46 − x Cu x Sn 11 ( x = 1 , 2, and 3) alloys was prepared by the arc melting method. The martensitic transition shifts to a higher temperature with increasing Cu concentration. The isothermal magnetization curves around the martensitic transitiontemperature show a typical metamagnetic behavior. Under a low applied magnetic field of 10 kOe , positive values of magnetic entropy change around the martensitic transitiontemperature are 14.1, 18.0, and 15.8 J ∕ kg K for x = 1 , 2, and 3, respectively. While in the vicinity of the Curie temperature of the austenitic phase, these negative values are 1.1, 1.0, and 0.9 J ∕ kg K for x = 1 , 2, and 3, respectively. The origin of the large entropy changes and the potential application for Ni 43 Mn 46 − x Cu x Sn 11 alloys as a working substance for magnetic refrigeration are discussed.