Effects of mechanochemical activation on the structural and electrical properties of orthorhombic LuFeO3 ceramics

Orthorhombic LuFeO 3 is an important member of rare-earth orthoferrites ReFeO 3 whose appealing physical features have drawn much attention due to its various potential applications. In this work, pure phase LuFeO 3 ceramics have been prepared by a mechanochemical activation-assisted solid-state reaction (MAS) method and conventional solid-state reaction (CSS) method for comparison. X-ray Diffraction (XRD) studies demonstrated that the mechanochemical activation process can lower the starting reaction temperature and substantially shorten the time to complete the reaction of LuFeO 3 ceramics. Besides, more homogeneous and highly denser LuFeO 3 ceramics can be obtained using the MAS method revealed by the density measurement and Scanning Electron Microscopy. It was revealed by XRD and Raman measurements that there is a little increase in lattice constant in the MAS sample compared to the CSS sample. The complex impedance spectra illustrated that the MAS sample has a much higher resistance than the CSS sample, which is caused by the higher density and fewer oxygen vacancies verified by X-Ray Photoelectron Spectroscopy. We believe that this study will contribute to solving the common leakage problems in ReFeO 3 ceramics and the investigation of its multiferroic properties.