Structural and magnetic properties of (Sm1-xPrx)3Fe27.5Ti1.5 [x=0.2, 0.5, 0.8, 1.0] and their nitrides

Abstract (Sm 1− x Pr x ) 3 Fe 27.5 Ti 1.5 [ x =0.2, 0.5, 0.8, 1.0] compounds belonging to the novel 3:29 class have been prepared in order to investigate the effects of the combination of rare earths having opposite signs of second-order Stevens coefficient on their structural and magnetic properties. The amounts of different phases have been estimated from the Rietveld analysis of powder X-ray diffractograms. The changes in the easy magnetization direction in these compounds are explained as the resultant of two competing anisotropies from the rare earths occupying the two crystallographically inequivalent sites, 2 a and 4 i . Nitrogenation has increased the saturation magnetization and Curie temperature which could be due to magnetovolume effect and the changes in the densities of states in the 3d band. Changes in the easy magnetization direction upon nitrogenation are due to the modification of rare earth anisotropy. 57 Fe Mossbauer spectra have been analyzed in a Wigner–Seitz cell approach.