Influence of different preparation method on the microstructure and physical properties of CuFeO2

Abstract

The single-phase CuFeO2 multiferroics material were achieved in crystal and ceramic forms successfully prepared by the optical floating zone with a low growth rate of 0.5 mm/h and high temperature solid state methods, respectively. All samples are delafossite structure. X-ray photoelectron spectroscopy spectra showed that there were different in the state of Cu iron. Positron annihilation lifetime spectra showed a decrease in the open volume of vacancy type defects in the crystal along with an increase in their concentration and the local electron density at the lattice was also changed compared to the ceramic sample. Raman spectra results proved that the vibration of the Cu–O bond was affected. Magnetic properties measurements indicated that the stability of antiferromagnetism and the interaction between magnetic domains of CuFeO2 are closely related to its internal defects, and the difference in internal defects reduces the transition temperature TN1 from 15.9 K in ceramic to 15.5 K in crystal.