Affiliation: | a Department of Physics, SungKyunKwan University, Suwon 440-746, Republic of Korea b Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784, Republic of Korea c Thin Film Materials Laboratory, Korea Research Institute of Chemical Technology, Yuseong, P.O. Box 107, Daejon 305-600, Republic of Korea |