Giant magneto-optical faraday effect of nanometer Fe-In₂O ₃ granular films

The giant magneto-optical Faraday effect of nanometer ferromagnetic metal-semiconductor matrix Fe-In₂O₃ granular films prepared by the radio frequency sputtering are studied. The result shows that the Faraday rotation angle θ _F value of the granular film samples with Fe volume fraction x = 35% is of the order of 10 ⁵(°)/cm at room temperature. Temperature dependence of the Faraday rotation angle θ _F of Fe_0.35(In ₂O₃)_0.65 granular films shows that θ _F value below 10 K increases rapidly with the decrease of the temperature, and when T = 4.2 K, θ _F value is 10 ⁶(°)/cm. Through the study of the dependence of low field susceptibility on temperature and the hysteresis loops at different temperatures, it has been found that when the temperature decreases to a critical point T _P = 10 K, the transformation of state from ferromagnetic to spin-glass-like occurs in Fe_0.35(In ₂O₃)_0.65 granular films. The remarkable increase of the Faraday rotation angle θ _F value of Fe _0.35(In₂O₃)_0.65 granular films below 10 K seems to arise from the sp-d exchange interaction of the granular film samples in the spin-glass-like state.