MAGNETIC PROPERTIES, MAGNETOCALORIC EFFECT AND CRITICAL PARAMETERS OF Ni50Mn50-xSbx alloy RIBBONS.

Abstract

Ni₅₀Mn_50-xSb_x (x = 11, 12, 13, 14 and 15) alloy ribbons are produced by using melt spinning and subsequent annealing. The X-ray diffraction data show that the samples with x =13÷15 are mainly structured with Ni₂MnSb single phase. The shape of thermomagnetization curve considerably depends on the Sb concentration and annealing process. The antiferromagnetic-ferromagnetic transition is clearly observed on the samples with x = 12÷14. Under the magnetic field change of 12 kOe, the maximum magnetic entropy change /ΔSm/max of the ribbons is about 1 J.kg^-1.K^-1. Based on the Landau’s phase transition theory and analyses of the magnetic data, the critical parameters of the alloys have been determined.