Structure and multiferroic properties of Eu-substituted BiFeO₃ ceramics

Abstract

Polycrystalline Bi_1−x Eu _x FeO₃ (x=0.00–0.25) ceramics were synthesized by the solid state reaction method with the rapid liquid phase sintering process. The effects of Eu substitution on the structure, and ferroelectric and magnetic properties of BiFeO₃ ceramics were investigated. X-ray diffraction measurements reveal that the structure of BiFeO₃ was changed from rhombohedral to orthorhombic and the impurity phases were decreased both due to Eu substitution. Raman spectra results also confirm that a structure transition occurs in the Eu concentration range of 0.15–0.20. The SEM investigation has suggested that the Eu substitution hinders the grain growth. Vibrating sample magnetometer measurements indicate ferromagnetism in Eu-substituted BiFeO₃ ceramics. It is found that the room temperature magnetic moment increases with increasing Eu concentration due to the suppressed or broken cycloid spin structure. Ferroelectric measurements show that Eu substitution enhances the polarization due to the significant decrease of the electric leakage of the samples. Therefore, the Eu-substituted BiFeO₃, or more complicated substituted BiFeO₃ based on Eu substitution, will have great potential for many practical applications.