Author/Authors :
Chuang، نويسنده , , P.Y. and Huang، نويسنده , , J.C.A. and Lu، نويسنده , , P.E. and Hsu، نويسنده , , H.S. and Sun، نويسنده , , S.J. and Yang، نويسنده , , Y.W. and Chen، نويسنده , , J.M and Lee، نويسنده , , C.H.، نويسنده ,
Abstract :
Co-doped amorphous carbon (Co:a-C) films, which comprise a homogeneously mixed carbon matrix phase with approximately 5 at.% cobalt, were deposited on quartz glass by radio frequency magnetron sputtering. A bias-dependent positive magnetoresistance (PMR) with a peak at a particular voltage was observed. The electronic structures were examined by ultraviolet photoelectron spectroscopy and X-ray absorption near edge spectroscopy. The spectroscopic results reveal that Co doping promotes the graphitization in the a-C matrix and the 3d orbital of Co is hybridized with sp2 states (DOSs) in the Co:a-C. The PMR effect is related to the modulation of the DOS of the Co:a-C films at the Fermi level by Zeeman splitting.
