Multiferroism at Room Temperature in BiFeO₃/BiCrO₃(111) Artificial Superlattices

Abstract

We report the fabrication of BiFeO3/BiCrO3(111) artificial superlattices with 1/1 stacking in a layer-by-layer growth mode on atomically flat SrTiO3(111) surfaces. While BiFeO3 and BiCrO3 are antiferromagnets having Fe–O–Fe and Cr–O–Cr bonds, these superlattices contain Fe–O–Cr bonds, in which ferromagnetic interaction is expected. Magnetization measurements at 300 K revealed that the magnetic moment per transition metal ion was 1.7 µB, suggesting ferromagnetic spin order. Ferroelectric behavior at room temperature was confirmed by an analysis using a scanning non-linear dielectric microscope.