The Ferroic Phase Transitions of BiFeO₃

BiFeO3 displays an abrupt first order transition from the polar structure R3c to centrosymmetric at TC = 830 °C. The ferroelectric transition is associated with abrupt changes in polar cation displacements and a large discontinuous volume. A continuous volume expansion occurs across the second order antiferromagnetic transition at TN = 370 °C. Electronic conductivity anomalies are associated with both phase transitions.