Dilatometric and high temperature X-ray diffractometric studies of La1−xMxCrO3 (M=Sr2+, Nd3+, x=0.0, 0.05, 0.10, 0.20 and 0.25) compounds

The phase transition, bulk and lattice thermal expansion behaviour of the strontium and neodymium substituted lanthanum chromites have been studied by dilatometry and high temperature X-ray powder diffractometry from room temperature to 1123 and 1073 K, respectively, in static air. The studies revealed that the temperature of the orthorhombic to rhombohedral phase transition, which occurred at ∼550 K in undoped LaCrO3, decreased on substitution of Sr2+ ions and increased on substitution of Nd3+ ions, systematically. However, the coefficients of average linear and volume thermal expansion (αl and αv) of LaCrO3 showed a marginal increase on Sr2+ substitution to different extent, whereas a reverse trend was observed with Nd3+ substitution. The phase transition temperatures and αl and αv of the compounds as determined by dilatometric and high temperature X-ray diffractometric methods are reported.