Weak Ferromagnetic Transition with a Dielectric Anomaly in Hexagonal Lu0.5Sc0.5FeO3

Lu1-xScxFeO3 (0 <= x <= 1) was synthesized by a conventional solid-state reaction. The hexagonal phase appeared at 0.4 <= x <= 0.6, between the perovskite phase (0 <= x <= 0.3) and the bixbyite phase (0.7 <= x <= 1). Structural, magnetic, and dielectric properties of hexagonal Lu0.5Sc0.5FeO3 were investigated. Synchrotron X-ray diffraction measurements revealed that the crystal structure of Lu0.5Sc0.5FeO3 is isomorphic to hexagonal ferroelectrics RMnO3 (R = rare earth ion) with a polar space group of P6(3)cm. A weak ferromagnetic transition with a dielectric anomaly occurred at a much higher temperature (162 K) than those in hexagonal RMnO3. Although remanent magnetization was observed below the transition temperature, it decreased to almost zero at 10 K These results indicate a strong antiferromagnetic interaction between ground-state Fe3+ ions on the triangular lattice.