Effect of rare earth doping on BiFeO3 magnetic and structural properties (La, Gd)

Abstract

In order to remove the incommensurate cycloid spin coupling in BiFeO 3 that inhibits this multiferroic compound of showing magnetoelectric effect, we doped this perovskite on Bi site with rare-earth ions (La, Gd), showing that the antiferromagnetic ordering with space modulated coupling of spins is broken. A correlation between the structure and the magnetic properties is found through Rietveld Refinement of X-Ray diffraction patterns, magnetic hysteresis curves and the hyperfine parameters obtained by Mossbauer Spectroscopy at room temperature, justified by the doping ion size that induces a magnetic structure distortion reflected in an increase of the coercive field and the remanent magnetization as well as in the hyperfine parameters behavior, linked with the structural phase transitions caused by the removal of the Bi 6s2 lone pair that induces structural distortions. It is also shown that the symmetries used are polar, that in principle can let the compounds keep a ferroelectric behavior. © 2010 IOP Publishing Ltd.