Size confinement and magnetization improvement by La3+ doping in BiFeO3 quantum dots

Nanometric multiferroic samples Bi1-xLaxFeO3; 0.05 <= x <= 0.40 were prepared using ceramic method. Structural and magnetic properties were investigated using XRD, TEM, magnetic susceptibility and M-H loop. The decrease in the lattice parameters is due to the difference between the ionic radii of Bi and La and this effect is compensated by the change in the atomic weight of the two elements which is reflected as a decrease in the density. The obtained results showed that all samples were antiferromagnetic in character. The small values of remnant and saturation magnetization indicated the canted type anti-ferromagnetism. Maximum coercivity H-c = 5265 Oe was obtained at x = 0.25. The magnetic susceptibility measurements show its size dependence due to long range spin arrangement. Improvement of the magnetization of BiFeO3 is achieved by La3+ at different doping levels. The obtained quantum dot size of the crystallites enhances their use in spintronic devices. (C) 2013 Elsevier Masson SAS. All rights reserved.