1. Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, United Kingdom
2. Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi,
Kohoku-ku, Yokohama 223-8522, Japan
3. Department of NANOscience, Institut Néel, CNRS, rue des Martyrs 38054, Grenoble, France
4. Laboratoire National des
Champs Magnetiques Intenses, CNRS-UJF-UPS-INSA, F-38042, Grenoble, France
5. College of Liberal Arts and Sciences, Anyang University, Gyeonggi-do 430-714, South Korea
6. Department of Physics, Yeungnam University, Gyeonsan 712-749, South Korea
7. Center
for Optoelectronic Convergence Systems, KIST, Seoul, 136-791, South Korea