1. Department of Physics Sungkyunkwan University Suwon 16419 Korea
2. Department of Physics Pukyong National University Busan 48513 Korea
3. Materials Science and Technology Division Oak Ridge National Laboratory Oak Ridge TN 37831 USA
4. Application Group, Korea I.T.S. Co. Ltd. Seoul 06373 Korea
5. Department of Physics Pusan National University Busan 46241 Korea
6. Busan Center, Korea Basic Science Institute Busan 46742 Korea