Multiferroic and in-plane magnetoelectric coupling properties of BiFeO3 nano-films with substitution of rare earth ions La~(3+) and Nd~(3+)

Single-phase multiferroic BiFeO3 and Bi(0.9)(La/Nd)(0.1)FeO3(doped with rare earth ions La-(3+) and Nd-(3+)) 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 BiFeO3 and Bi(0.9)(La/Nd)(0.1)FeO3 exhabited 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 BiFeO3 crystals, and it enhanced effectively the in-plane ME coupling(the ME coupling coefficient αE increased from 0.13 in the pure BiFeO3 to 0.21 in Bi(0.9)La(0.1)FeO3 and 0.34 V/(Oe·cm) in Bi(0.9)Nd(0.1)FeO3). The mechanism of these phenomena was investigated systematically.