Effect of La doping in the multiferroic compound BiFeO3

Abstract We have performed magnetization and magnetocapacitance measurements on ceramic samples of the multiferroic series Bi 1− x La x FeO 3 for 0≤ x ≤.0.25. We show that doping with La reduces the transition magnetic field from the spatially modulated state to a homogenous one and increases the magnetocapacitance, these effects being the strongest for x =0.15, which is the highest concentration for maintaining the non-centrosymmetric rhomboedral structure (R3c) of BiFeO 3 . For highest La content ( x ≥0.17), analysis of the XRD patterns shows that the lattice symmetry gradually changes to orthorhombic (C222), giving rise to an enhancement of the latent magnetization and to a drop of the magnetodielectric constant.