MAGNETIC-PROPERTIES OF ORDERED PEROVSKITES BA3CAU2O9 AND BA3SRU2O9

Uranium complex oxides with the ordered perovskite structure, Ba3CaU2O9, and Ba3SrU2O9, were prepared, and their magnetic susceptibilities were measured in the temperature range between 4.2 K and room temperature. No magnetic cooperative phenomenon was found down to 4.2 K. The effective magnetic moments of Ba3CaU2O9 and Ba3SrU2O9 were 1.24 μB and 0.56 μB, respectively. Electron paramagnetic resonance (EPR) measurements were carried out for these compounds, but no EPR spectra which are ascribable to the U5+ ion in an octahedral crystal field were observed. The crystal field parameters of these compounds were determined from the analysis of the optical absorption spectra published previously. The effective moments and temperature-independent paramagnetic susceptibilities were calculated and compared with the experimental results. © 1994 Academic Press. All rights reserved.