Enhanced ferroelectricity and ferromagnetism in La_1−xBi_xCrO₃ by Bi³⁺ substitution

The ferroelectric and magnetic properties of the perovskite solid solution, (1 − x)LaCrO_3–xBiCrO₃, have been investigated. While pure LaCrO₃ does not show ferroelectric hysteresis even at 77 K, the solid solution of La_1−xBi_xCrO₃ with x = 0.1, 0.2, 0.3, and 0.35 displays ferroelectric hysteresis, with the remanent polarization increasing with the increase of the Bi³⁺ content. Using a superconducting quantum interference device, the magnetization was measured versus temperature under field cooling (FC) and zero field cooling (ZFC) conditions. Magnetic hysteresis has been found in La_1−xBi_xCrO₃ (0.1 ⩽ x ⩽ 0.3) below the Néel temperature, T_N. With the increase of Bi³⁺ content, T_N decreases, while the magnetization below T_N is enhanced. While the ferroelectric and magnetic properties could be due to different origins, the Bi substitution results in both ferroelectric and magnetic enhancements in the (1 − x)LaCrO_3–xBiCrO₃ solid solutions.