1. Department of Physics,
2. Department of Physics, University of Connecticut, Storrs, CT 06269, USA.
3. National Synchrotron Light Source,
4. Division of Materials Sciences, Brookhaven National Laboratory, Upton, NY 11973–5000, USA.
5. School of Physics, The University of New South Wales, Post Office Box 1, Kensington, New South Wales, Australia 2033.
6. Superconductivity Research Laboratory, ISTEC, 10-13, Shinonome I-chrome, Koto-ku, Tokyo 135, Japan.