Preparation and Faraday effect of EuS microcrystal-embedded oxide thin films

EuS microcrystal-embedded SiO2, Al2O3, and TiO2 thin films have been prepared by using rf sputtering method. X-ray diffraction analysis indicates that EuS microcrystal is precipitated as a single phase in Al2O3 and TiO2 films while precipitation of EuS is not detected in SiO2 film. Faraday effect attributable to the 4f7–4f65d transition of Eu2+ in EuS microcrystalline phase is observed in Al2O3 and TiO2 films. In particular, Faraday rotation angle observed for EuS-embedded TiO2 film is large; for instance, the magnitude of Verdet constant for as-deposited TiO2 film prepared without heating of substrate during the sputtering is 0.15 deg/cm Oe at wavelength of 700 nm. This value is larger by two orders of magnitude than those of Eu2+- or Tb3+-containing oxide glasses which show the largest Faraday rotation angle among rare-earth-containing glasses, and is comparable to the value for EuSe single crystal.