Vortex domain structures and room temperature multiferroic characteristics in h-Yb_1-xIn_xFeO₃ ceramics

In the present work, Yb_1-xIn_xFeO₃ multiferroic ceramics with stable hexagonal structure were obtained by introducing chemical pressure, where the unique ferroelectric domain structures of sixfold vortex combined with tenfold vortex with a typical size of ~400 nm were determined. Symmetry of the present system evolved from centrosymmetric orthorhombic Pbnm (x=0-0.4) to non-centrosymmetric hexagonal P63cm (x=0.5&0.6) with the ferroelectric polarization up to 3.2 μC/cm², and finally to centrosymmetric hexagonal P63/mmc (x=0.7&0.8). The Curie point decreased monotonically from 723 K to a temperature below room temperature with increasing x, and the antiferromagnetic phase transition above room temperature was determined for all compositions. Meanwhile, a large linear magnetoelectric coefficient (α_ME) up to 0.96 mV/cm Oe was obtained at room temperature, and this indicated the great application potential for magnetoelectric devices.