Structural and magnetic properties of multiferroic hexagonal Lu0.5(Sc1-xInx)0.5FeO3 ceramics

Abstract

In this work, we have investigated the structural and magnetic properties of hexagonal Lu0.5(Sc1-xInx)0.5FeO3 ceramics synthesized by solid state reaction. All samples were identified to crystalize in the hexagonal structure with polar space group (P63cm). The lattice parameters, both a and c, increase with In-substitution, owing to larger ionic radius of In3+ in comparison with that of Sc. Meanwhile, the c/a ratio increases from 1.9952 for x = 0 to 2.0308 for x = 1.0. All samples undergo an antiferromagnetic transition, accompanied by a dielectric anomaly, which is the fingerprint of magnetoelectric coupling in hexagonal LuFeO3 systems. The Néel temperature (TN) shifts towards lower temperature with the increase of In-substitution, demonstrating the weakening magnetic interaction stemming from smaller structural distortion due to smaller tilting angle of FeO5 bipyramids. It is fascinating that the increase of c/a ratio brings about a decrease of TN after the In-substitution for Sc. Another magnetic anomaly was observed above the TN (around 265 K) in Lu0.5Sc0.5FeO3. The temperature of magnetic anomaly increases towards higher temperature with the increase of In-substitution and rises above room temperature in Lu0.5In0.5FeO3. It can be suggested that the magnetic order is more complex than that obtained in previous works, and the room-temperature multiferroics is attainable for application in hexagonal RFeO3 systems.