Crystal Structure of Bi1 – xPrxFeO3 Multiferroics at the Rhombohedral–Orthorhombic Phase Boundary

Resumo

The crystal structures of Bi_1 – xPr_xFeO₃ solid solutions in the vicinity of the transition from the polar rhombohedral phase to the nonpolar orthorhombic phase have been analyzed by X-ray diffraction, transmission electron microscopy, and differential scanning calorimetry. These methods made it possible to reveal the specific features of the change in the crystal structures of the solid solutions with an increase in temperature in dependence of their structural state at room temperature. The analysis of the structural data indicates the presence of antipolar orthorhombic phase in the compounds with dominant rhombohedral phase at the temperature transition to the nonpolar state. The evolution of the crystal structures of Bi_1 – xPr_xFeO₃ solid solutions with a change in the concentration of praseodymium ions and temperature has been considered, and the role of the antipolar orthorhombic phase as an intermediate phase in the structural transition from the rhombohedral phase to the nonpolar orthorhombic phase has been discussed.