Multiferroic and in-plane magnetoelectric coupling properties of BiFeO3 nano-films with substitution of rare earth ions La3+ and Nd3+

Single-phase multiferroic BiFeO3and Bi0.9(La/Nd)0.1FeO3(doped with rare earth ions La3+and Nd3+) films grown on(111)-Pt/Ti/SiO2/Si substrate were prepared via sol-gel method and a subsequent rapid thermal process. The phase composition, microstructure, ferroelectric, dielectric, ferromagnetic properties were investigated, and meanwhile, the in-plane magnetoelectric(ME) coupling effects of the films were reported and studied for the first time in this work. Structural characterization by X-ray diffraction and scanning electron microscopy showed that both BiFeO3and Bi0.9(La/Nd)0.1FeO3exhabited a rhombohedral structure with(111) preferred orientation. The results of the physical properties indicated that the introduction of rare earth ions improved significantly the polarization, magnetization and dielectric properties than the undoped BiFeO3crystals, and it enhanced effectively the in-plane ME coupling(the ME coupling coefficient αE increased from 0.13 in the pure BiFeO3to 0.21 in Bi0.9La0.1FeO3and 0.34 V/(Oe·cm) in Bi0.9Nd0.1FeO3). The mechanism of these phenomena was investigated systematically.