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 θF value of the granular film samples with Fe volume fraction x = 35% is of the order of 105(°)/cm at room temperature. Temperature dependence of the Faraday rotation angle θF of Fe0.35(In2O3)0.65 granular films shows that θF value below 10 K increases rapidly with the decrease of the temperature, and when T = 4.2 K, θF value is 106(°)/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 TP = 10 K, the transformation of state from ferro- magnetic to spin-glass-like occurs in Fe0.35(In2O3)0.65 granular films. The remarkable increase of the Faraday rotation angle θF value of Fe0.35(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.
