1. National High Magnetic Field Laboratory (NHMFL), Florida State University, Tallahassee, FL 32310, USA.
2. Department of Physics, Universidad de Los Andes, Bogotá 111711, Colombia.
3. Departamento de Ciencias Naturales, Facultad de Ingeniería y Ciencias Básicas, Universidad Central, Bogotá 110311, Colombia.
4. Department of Physics, Florida State University, Tallahassee, FL 32310, USA.
5. Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany.
6. Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
7. Brookhaven National Laboratory (BNL), Upton, NY 11973, USA.
8. Applied Physics Department, Yale University, New Haven, CT 06520, USA.
9. Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, NY 14853, USA.