The phase transition in PrGa(0.95)Mg(0.05)O(3) at elevated temperatures

PrGa(0.95)Mg(0.05)O(3) was synthesized by a standard solid-state technique, having an orthorhombic structure determined from X-ray diffraction (XRD) data at room temperature. At high temperature, an inflection is found on the Ln sigma T vs. 1/T curve at about 550 degrees C. The inflection can also be observed on thermal expansion vs. temperature curve at about 530 degrees C. Furthermore, the number of Raman modes between 200 and 400 cm(-1) decreases and the peak at about 190 cm(-1) weakens at about 450 degrees C. The results indicate a structural transition from orthorhombic to tetrahedral or rhombohedral. (C) 2008 Elsevier Ltd. All rights reserved.