Improved magnetic and magnetoelectric properties in BaFe₁₂O₁₉ nanostructures

Abstract

The structural, magnetic and magnetoelectric properties were investigated for sol-gel prepared BaFe₁₂O₁₉ nanorods and plate-like nanoparticles. Based on comparative experiments with bulk ceramics, it is found that larger structural distortion is present in nanostructures, which could cause the enhancement of magnetocrystalline anisotropy and the off-center displacement of Fe³⁺ ions, and thus result in improved magnetic and magnetoelectric properties in BaFe₁₂O₁₉ plate-like nanoparticles. Meanwhile, the local (Fe²⁺-Fe³⁺) dipoles, which usually appear during a high temperature sintering process, can also contribute to the negative magnetoelectric effect of BaFe₁₂O₁₉ nanorods and a large room temperature magnetodielectric coefficient of about -13% is observed at 10⁴ Hz and 9 kOe.