Magnetic properties and magneto-optical effect of Co0.5Fe2.5O4 nanostructured films

Abstract

${\mathrm{Co}}_{\text{0.5}}{\mathrm{Fe}}_{\text{2.5}}{\mathrm{O}}_4$ ferrite films with nanostructure have been prepared by rf sputtering on a quartz substrate and annealed at temperatures from 400 to 600 °C in air. The magnetic properties and magneto-optical effect have been studied. It has been found that nanocrystalline ${\mathrm{Co}}_{\text{0.5}}{\mathrm{Fe}}_{\text{2.5}}{\mathrm{O}}_4$ films exhibit good magnetic properties and a large magneto-optical effect. The magnetization, coercivity, remanence ratio, and maximum energy product are 455 emu/cm³, 2.8 kOe, 0.72 MGOe, and 2.4 MGOe, respectively. The magneto-optical Faraday rotation is <−3.4°/μm at short wavelength and 4°/μm at the wavelength of 740 nm. These characteristics make them very promising to be used for magneto-optical recording and for permanent magnets. The influence of the distribution of ${\mathrm{Co}}^{\text{2+}}$ ions on magnetic properties and magneto-optical effect has been discussed.