Abstract
SnO2 (3 % Sb) films were implanted with 5×1016 57Fe ions/cm2 at the substrate temperature of 500°C, and annealed at temperatures between 400°C and 800°C. These films were characterized by depth selective conversion electron Mössbauer spectroscopy (DCEMS) using a back scattered type of a gas proportional counter, and measured by a Kerr effect magnetometer. Kerr effect measurements of the SnO2 films showed ferromagnetism at room temperature. The Mössbauer spectra of the as-implanted films consisted of paramagnetic doublets of Fe3+ and Fe2+ species and two broad sextets, which showed site A and site B of fine grain magnetite. The Kerr rotation angles increased step by step with post-annealing up to 700°C. This phenomenon was attributed mainly to ferromagnetic maghemite produced by post-annealing. It was found from DCEMS analysis that the maghemite with relatively large grains exists more in top layer than deep layer.
