Synthesis, characterization and studies on magnetic and electrical properties of LaAlyFe1-yO3 nanomultiferroic

Multiferroic LaAlyFe1-yO3; 0.00 <= y <= 0.20 were successfully synthesized using citrate autocombustion method and their properties were systematically studied. All the samples were crystallized in a perovskite structure. The evaluation of the unit-cell parameters by X-ray diffraction technique revealed that the lattice constants and volume of the unit cell decreased along with increase of Al content, while the Fe-O octahedra became less distorted. The Goldschmidt tolerance factor for the perovskite increases from 0.905 for LaFeO3 to 0.914 for LaAl0.2Fe0.8O3 confirming that the crystal structure is orthorhombic. All the magnetic parameters such as mu(eff), chi(M), and magnetization (M-RT) decrease as Al content increases, while Neel temperature indicates the highest value ( 834 K) at y = 0.1. The magnetic measurements revealed that it has a superparamagnetic behavior with coercive field H-c nearly zero. Dielectric and activation energy results agree well with the other measurements. (C) 2012 Elsevier B.V. All rights reserved.