1. Mechanical Engineering Department, Florida State University, Tallahassee, Florida 32310, USA
2. National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, USA
3. Department of Physics, University of Florida, Gainesville, Florida 32611, USA
4. Department of Physics, Yale University, New Haven, Connecticut 06515, USA
5. School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT, United Kingdom