Phase transitions, polar and magnetic orderings in perovskites of the BiFeO3–BiCrO3 series

The high-pressure stabilized perovskite phases of the BiFe 1- x Cr x O 3 solid solutions (0 ≤ x ≤ 1) were studied in respect of their stability at ambient pressure, phase coexistence and phase transitions as well as dielectric properties and magnetic behaviour. The as prepared phases with x ≤ 0.50 are the rhombohedral R 3 c . In the compositional range of 0.55 ≤ x ≤ 0.90, the solid solutions are the antipolar orthorhombic Pnma , while the monoclinic C 2/ c phase is formed when x ≥ 0.95. Upon heating, all the studied compositions exhibit structural transition into a high-temperature non-polar orthorhombic Pnma modification. The transition is reversible; the only exception is the case of the solid solution with x = 0.55, which transforms to the two-phase mixture ( R 3 c + antipolar Pnma ) upon cooling. The BiFe 1- x Cr x O 3 ceramics demonstrate high dielectric constant yet a relatively high dielectric loss, which grows with increasing temperature. Dielectric dispersion likely caused by ferroelectric domain was observed and activation energy was estimated as a function of chromium content. The composition with x = 0.95 shows a spin re-orientation transition, which is suppressed when x ≤ 0.90. In the Cr-rich compositional range, a magnetization reversal effect below the Néel temperature was observed. • The BiFe 1- x Cr x O 3 solid solutions (0 ≤ x ≤ 1) was synthesized under high pressure • x -ranges of rhombohedral, anti-polar orthorhombic and monoclinic phases were found • Increasing temperature leads to reversible transition to non-polar orthorhombic phase • The BiFe 1- x Cr x O 3 ceramics demonstrate high permittivity yet high dielectric loss • In the Cr-rich x -range, a magnetization reversal effect below T N was observed