Phase transition, dielectric, ferroelectric and ferromagnetic properties of La-doped BiFeO3-BaTiO3 multiferroic ceramics

0.70Bi(1-x)La(x)FeO(3)-0.30BaTiO(3) + 1 mol% MnO2 multiferroic ceramics were prepared by using the solid state reaction and their phase structure, dielectric, ferroelectric and ferromagnetic properties were studied. All the ceramics possess perovskite structure and exhibit good insulation and densification. A morphotropic phase boundary of rhombohedral and tetragonal phases is formed at x = 0.02. As the concentration of La3+ is increased, the ferroelectric-paraelectric phase transition of the ceramics at Curie temperature becomes gradually more diffusive. A small amount of the substitution of La3+ for Bi3+ improves effectively the ferroelectricity of the ceramics and the optimum remanent polarization of 27.2 mu m/cm(2) reaches at x = 0.04. After the addition of La3+, the ferromagnetism of the ceramics is greatly enhanced and the remanent magnetization M-r monotonously increases from 0.0321 to 0.147 emu/g with x increasing from 0 to 0.10. Our results show that the ceramics possess simultaneously improved ferroelectric and ferromagnetic properties and may a promising candidate for room-temperature multiferroic materials.