Room temperature ferromagnetism and hopping conduction in Pt NCs/Al2O3 films

In this work, Pt nanocrystals (NCs) were embedded into different oxide films by codeposition of Pt and oxide at 400 °C and 10−8 Torr using a pulse laser deposition system. Films of Pt (25 mol. %) NCs embedded in (Al2O3, ZnO, or SnO2) matrix showed room temperature ferromagnetism (RTFM), while Pt (25 mol. %) NCs/(MgO or SiO2) films were not magnetic. The detailed study of Pt NCs/Al2O3 films with different concentrations of Pt revealed that RTFM depended on Pt NC size and conductivity of the film. Resistance-temperature study of this film showed that the hopping conduction may be associated with RTFM.