Phase relations and lattice thermal expansion studies in the Ce0.50RE0.50O1.75 (RE = rare-earths)

The synthesis, characterization and lattice thermal expansion of a series of compounds with the general composition Ce0.50RE0.50O1.75 (RE = trivalent rare-earth ion) are being reported. XRD pattern of each product was refined to know the lattice parameters in each case under the conditions of slow-cooling from 1400 °C. It was observed that the compositions with a 50 mol% of REO1.5 substitution (RE = La to Ho) were all cubic solid solutions (either F-type or C-type). A steady decrease in the cubic lattice parameter value was observed on going from La to Ho, in the Ce0.50RE0.50O1.75 series. The compositions with a 50 mol% of REO1.5 substitution (RE3+ = Er3+, Yb3+, Lu3+ and Sc3+) were found to be biphasic. The lattice thermal expansion behavior, as investigated by a high temperature-XRD, for each composition in the temperature range 293–1473 K is also being reported.