MAGNETOCALORIC EFFECT AROUND CURIE TEMPERATURE IN Ni50-x CuxMn38Sn12B3 SHAPE MEMORY RIBBONS

Abstract

The magnetocaloric effect in Ni50-xCuxMn38Sn12B3 ribbons depending on the Cu substitution (x= 0, 1, 3) was investigated around the Curie temperature. The purpose of the present study was to analyze the magnetocaloric effect around a second order phase transition (around the Curie temperature) which has a smaller thermal hysteresis compared to a first order phase transition (Martensitic transition). The Curie temperature of the ribbons shifted to higher temperatures with increasing Cu content. A conventional magnetocaloric effect (MCE) was observed around the Curie temperature when the ribbons are subjected to a magnetic field change of 5 T. The magnetic entropy changes were calculated based on the isothermal magnetization data using thermodynamic Maxwell equation. The highest magnetic entropy change and the refrigerant capacity was obtained for the x=1 ribbon.