Magnetic excitations in the spin-1 anisotropic antiferromagnet NiCl 2-4 SC ( NH 2 )

C. Psaroudaki,1,2 S. A. Zvyagin,3 J. Krzystek,4 A. Paduan-Filho,5 X. Zotos,1,2,6 and N. Papanicolaou1,6 1Department of Physics, University of Crete, GR-71003 Heraklion, Greece 2Foundation for Research and Technology–Hellas, GR-71110 Heraklion, Greece 3Dresden High Magnetic Field Laboratory (HLD), Helmholtz-Zentrum Dresden-Rossendorf (HZDR), DE-01314 Dresden, Germany 4National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA 5Instituto de Fisica, Universidade de São Paulo, BR-05315-970 São Paulo, Brazil 6Institute of Plasma Physics, University of Crete, GR-71003 Heraklion, Greece (Received 17 November 2011; published 17 January 2012)