The saturation magnetization (M_s), antiferromagnetic transition point (T_N), and the off-center displacements of Bi and Fe ions have been measured as a function of particle size in nanoscale BiFeO3. T_N decreases down to ~550 K for particles of size ~5 nm from ~653 K in bulk while M_s rises by more than an order of magnitude. Analysis of crystallographic structure from Rietveld refinement of x-ray diffraction patterns shows significant rise in off-center displacements of Bi (del_Bi) and Fe (del_Fe) ions within a unit cell with the decrease in particle size. The net unit-cell polarization P_S too, is found to be larger in nanoscale regime.
@article{arxiv.1012.4288,
title = {Particle size dependence of magnetization and non-centrosymmetry in nanoscale BiFeO3},
author = {Sudipta Goswami and Dipten Bhattacharya and P. Choudhury},
journal= {arXiv preprint arXiv:1012.4288},
year = {2011}
}
Comments
4 pages including 3 figures; J. Appl. Phys. (Proc. 55th Annual MMM Conference; submitted)