Nanostructure magneto-optical thin films of rare earth (RE=Gd,Tb,Dy) doped cobalt spinel by sol–gel synthesis

Nanocrystalline CoFe1.9RE0.1O4 [rare earth (RE=Gd,Tb,Dy)] films have been prepared by the sol–gel route, and their polar magneto-optical (MO) Kerr rotation and ellipticity have been determined in the spectral range of 4000–8000 A. The films are composed of nanometer grains with the spinel structure. RE doped cobalt spinel ferrites are found to have dramatic changes in magnetic and MO properties, with increases in their coercive force and enhancement of the MO rotation in the Tb3+ doped sample.