Enhanced magneto-optical Kerr effects in nanocrystalline Sc-doped CoFe2O4 thin films

Nanocrystalline CoFe2−xScxO4 (x=0–0.4) thin films were prepared on silicon substrates at reduced temperature by a sol–gel process, and the doping effects of scandium on the microstructure, magnetism and polar magneto-optical Kerr effects of the as-deposited films were examined. It was shown that the intensities of both of the Kerr rotation peaks increase with the doping content x of Sc3+. The increase for the peak at 540 nm is due to the decrease of the electrostatic polarization of O2− resulting from the relatively large radius of Sc3+, and that for the peak at 620 nm was a result of the migration of Co2+ from octahedral to tetrahedral sites in the presence of the dopant of Sc3+.