EFFECT OF MANGANESE SUBSTITUTION IN R2ALFE16-XMNX (R = Y, HO, ND AND PR) COMPOUNDS ON STRUCTURAL AND MAGNETIC-PROPERTIES

The structural and magnetic properties of R2AlFe16-xMnx (0 less than o r equal to x less than or equal to 8 for Y, Ho, 0 less than or equal t o x less than or equal to 10 for Pr, 0 less than or equal to x less th an or equal to 16 for Nd)compounds have been investigated by means of X-ray diffraction and magnetization measurements. The R2AlFe16-xMnx co mpounds have a hexagonal Th2Ni17-type structure for R = Y and Ho, and a rhombohedral Th2Zn17-type structure for Nd and Pr. With increasing x , the unit-cell volumes have a small increase initially, followed by a greater linear increase. The Curie temperature and the saturation mag netization of these compounds show marvelous drop with increasing x. C ompensation point was observed in the temperature dependence of the ma gnetization for Ho2AlFe12Mn4 compound.