Composition dependent magnetic and ferroelectric properties of hydrothermally synthesized GdFe_1−xCr_xO₃ (0.1 ≤ x ≤ 0.9) perovskites

Abstract

The hydrothermal synthesis and magnetic, dielectric and ferroelectric property characterization of ABO₃-perovskite GdFe_1-xCr_xO₃ (0 < x < 1) are reported. The mineralizer KOH plays a critical role in the perovskite structure of the sample. The Fe/Cr ratio of the final crystal is controlled by the alkalinity in the initial reaction mixtures. The lattice parameters and magnetic ordering transition temperature have a close relationship with the Fe/Cr ratio. The temperature dependent magnetic properties of GdFe_1-xCr_xO₃ (0 < x < 1) samples show a close relationship with substituent ratios of Cr³⁺. The occurrence of ferromagnetic behavior in all of the as-prepared samples comes from the coexistence of canted-antiferromagnetism due to the double exchange effect of Fe-O-Fe and Cr-O-Cr and ferromagnetism due to superexchange interaction of Fe-O-Cr. A large spontaneous polarization was observed in GdFe_1-xCr_xO₃ at room temperature, exhibiting a clear ferroelectric hysteresis loop, which indicates the ferroelectric behavior in this system. This work not only provides an effective route to the controllable synthesis of B-site doped REFe_1-xCr_xO₃ perovskite structure materials, but also presents a comprehensive study of the tunable effect of ionic doping on ferroelectric properties.