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TiO2-based magnetic semiconductors with high Co doping concentrations (Ti1-xCoxO2) were synthesized under thermal nonequilibrium condition by sputtering machine. Microstructure and composition analysis by transmission electron microscopy, x-ray photoelectron spectroscopy, and electron energy-loss spectroscopy indicated that Co element was incorporated into TiO2 to form Ti1-xCoxO2 compound. The direct evidence for the compositional inhomogeneity of the Ti1-xCoxO2 compound was given. Room temperature ferromagnetism with high magnetization was obtained, which could be attributed to the intrinsic properties of the amorphous magnetic semiconductor. The electrical transport in a low temperature range was explained by spin-dependent Efros’s variable range hopping, and correspondingly an exponential function of the magnetoresistance versus T-1/2 was found. [ABSTRACT FROM AUTHOR]

Ti[O.sub.2]-based magnetic semiconductors with high Co doping concentrations ([Ti.sub.1-x][Co.sub.1-x][O.sub.2]) are synthesized under thermal nonequilibrium condition by sputtering machine. Microstructure and composition analysis has indicated that Co element is incorporated into Ti[O.sub.2] to form [Ti.sub.1-x][Co.sub.x][O.sub.2] compound and the magnetic transport has shown the spin-dependent Efros's variable range hopping behavior in the low temperature range below 80 K.