Room temperature ferromagnetism in pure and ion-doped SnO2 nanoparticles

Abstract

Using a microscopic model taking into account the spin–phonon interactions we have studied the magnetic properties of pure and ion-doped SnO2 nanoparticles (NPs). The magnetization M in pure SnO2 NPs is due to surface oxygen vacancies. By doping with magnetic Co ion we observe a maximum in M for small Co-concentration, x = 1%, whereas for nonmagnetic Cu ion M increases with x. By Co-doping there is a local distribution for small Co-concentration, whereas by Cu this is not the case. It is shown that there is a strong connection between the lattice and M. The results are in good agreement with the experimental data.