Finite size versus surface effects on magnetic properties of antiferromagnetic particles

Abstract

The observation of finite magnetic moment in antiferromagnetic materials is quite unusual and has been immensely investigated in nanoparticle systems. Here, the structural and magnetic properties of NiO particles are explored by x-ray diffraction, extended x-ray absorption fine structure, and magnetization measurements. Using similar-sized particles with different surface defect structure, we show that the observed magnetic enhancement, which is present even beyond finite-size limit, is due to the surface effects. However, the well known spin glass freezing is found to occur only in nano-regime.