论文部分内容阅读
A series of Nd2.1Y0.9Fe27.5Ti1.5-xMox (0.0＜x＜1.5) intermetallic compounds have been synthesized successfully and studied by means of X-ray powder diffraction.Rietveld analysis of XRD patterns showed that the main phases of all compounds crystallize in the monoclinic Nd3(Fe,Ti)29-type structure with space group A2/m and a small amount of 1:12-type phases behave as impurities.The preferential occupancies of Y over the 2a and 4i crystallographic sites have been determined by Rietveld refinement of the XRD patterns.It is found that the positions of Y in the 2a and 4i sties in the R3(Fe,M)29-type structure are not random and Y preferentially occupies the 4i sites.This behavior has been mainly attributed to the thermodynamics effect and can be explained by calculating the enthalpies of mixing between rare earth (Nd/Y) and stabilizing element (Ti/Mo)using Miedemas model.Pacs:75.50.Ww; 61.66.Dk; 61.10.Nz