TriclinicBiFeO3: A room-temperature multiferroic phase with enhanced magnetism and resistivity

The magnetic and transport properties of ${\mathrm{BiFeO}}_{3}/{\mathrm{La}}_{2}{\mathrm{NiMnO}}_{6}$ (BFO/LNMO) composite were investigated both experimentally and theoretically. Unlike the normal rhombohedral $(R3c)$ phase, BFO in composites is crystallized in the triclinic phase $(P1)$. Interestingly, the composites demonstrate a significant enhancement in magnetization and magnetoelectric coupling and show higher resistivity than regular BFO $(R3c)$. As LNMO has its Curie temperature at 280 K, the room temperature and above room temperature magnetic contribution in the composites is expected to be from the triclinic BFO phase. Experimentally observed enhancement in magnetization is validated using classical Monte Carlo simulation and density functional theory (DFT) calculations. The calculations reveal higher magnetic moments in triclinic BFO as compared to the rhombohedral BFO. Overall, this study reveals triclinic BFO as a promising room temperature multiferroic phase which is helpful to optimize the multiferroicity of BFO and achieve wider applications in future.