Structural transitions and conductivity of BaPrO3 and BaPr0.9Y0.1O3−δ†
Abstract
The temperature dependence of the crystal structures of the perovskites BaPrO3 and BaPr0.9Y0.1O3−δ has been determined between room temperature and 900 °C using time-of-flight c → Pm
m which occur at T ≈ 240, ≈ 375, and ≈ 860 °C for BaPrO3. The stability fields of the Pnma and Pm
m structures are lowered markedly by the presence of yttrium on the B-site. The first and last structural transitions are assigned as continuous events, and analysis of the octahedral tilt angle order parameter suggests the latter is tricritical in nature. The Imma → R
c transition is expected to be discontinuous first order and hysteresis effects in