EFFECT OF INHOMOGENEITY ON MAGNETIC PROPERTIES, X-RAY DIFFRACTION AND 31P NMR LINEWIDTHS IN UP1-XSX POWDERS

The wide temperature range at which transitions occur between magnetic structures, and the coexistence of magnetic structures in the UP 1-xSx system are attributed to the incomplete homogeneity of the powder samples. The inhomogeneity affects the linewidths of the x-ray diffractometer traces, the 31P nuclear magnetic resonance (NMR) lines in the paramagnetic state, and the magnetic properties of UP 1-xSx. The firing treatment of UP broadens the x-ray lines, while a second homogenization of UP0.72S0.28 sharpens the x-ray and 31P NMR lines and decreases the portion of the antiferromagnetic structure that coexists with the major ferromagnetic phase at low temperatures. The composition ranges (inhomogeneity widths) deduced from the x-ray line broadening are about 0.1x0, where x0 is the mean sulfur concentration. The upper limits of the inhomogeneity widths obtained from the excessive 31P NMR linewidths and the widths of the magnetic transitions are in fair agreement with the inhomogeneity widths based on the x-ray data. © 1969 The American Institute of Physics.