Affiliation: | a Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764, Korea b Center for NanoBioEngineering and Spintronics, Chungnam National University, 220 Gungdong, Yuseong-gu, Daejeon 305-764, Korea c Department of Physics, Andhra University, Visakhapatnam 530003, India |