The first-order magnetization process (FOMP) in NdFe 9Si 2C x ( x=0.5,1.0,1.5)

Abstract

The crystallographic and magnetic properties of RFe 9Si 2C x (R=Ce,Nd; x=0.5,1.0,1.5) with BaCd 11-type structure are studied. The structure is tetragonal, belonging to the space group I4 1/ amd with Nd in 4a site, Fe in 4b, 32i and half of 8d sites, Si in the left half of 8d site, and C in 8c site. The first-order magnetization process (FOMP) transition occurred in NdFe 9Si 2C x ( x=0.5,1.0,1.5) at low temperature. The critical field increases with the carbon content, and decreases with the increase in temperature. The magnetization curves of Nd(Fe,Si) 11C x are calculated to simulate the FOMP. The calculated curves indicate a type-I FOMP transition. In addition, the crystal-field coefficients A nm are calculated by point charge model, and the molecular field coefficients n RFe and n FeFe are obtained based on the molecular-field model.