[1] Florida State Univ, NHMFL, Tallahassee, FL 32310 USA
[2] Univ Los Andes, Dept Phys, Bogota 111711, Colombia
[3] Univ Cent, Fac Ingn & Ciencias Basicas, Dept Ciencias Nat, Bogota 110311, Colombia
[4] Florida State Univ, Dept Phys, Tallahassee, FL 32310 USA
[5] Max Planck Inst Chem Phys Solids, D-01187 Dresden, Germany
[6] Los Alamos Natl Lab, Los Alamos, NM 87545 USA
[7] Brookhaven Natl Lab, Upton, NY 11973 USA
[8] Yale Univ, Appl Phys Dept, New Haven, CT 06520 USA
[9] Cornell Univ, Lab Atom & Solid State Phys, Ithaca, NY 14853 USA
[10] Northrop Grumman Corp, Linthicum, MD 21090 USA