Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 2: Symposium: High Magnetic Field Phenomena in Low Dimensional Magnets
TT 2.6: Vortrag
Montag, 25. Februar 2008, 12:00–12:15, H 0104
Excitation hierarchy of the spin-1 large-D system NiCl2-4SC(NH2)2 — •S.A. Zvyagin1, J. Wosnitza1, C.D. Batista2, J. Krzystek3, V.S. Zapf4, M. Jaime4, A. Paduan-Filho5, M. Tsukamoto6, and N. Kawashima6 — 1Hochfeld-Magnetlabor Dresden/Forschungszentrum Dresden - Rossendorf — 2LANL, USA — 3NHMFL, USA — 4NHMFL/LANL, USA — 5Sao Paulo University, Brzail — 6ISSP, University of Tokyo, Japan
NiCl2-4SC(NH2)2 (known as DTN) is an S=1 chain system with the easy-plane anisotropy dominating over the exchange interaction (so-called large-D system) and a new candidate for studying the field-induced Bose-Einstein condensation of magnons. The excitation spectrum of DTN has been investigated by means of tunable-frequency ESR technique in fields up to 25 T. Based on analysis of the magnon excitation spectrum, a revised set of spin-Hamiltonian parameters was obtained. These values were used to calculate the AFM phase boundary, low-temperature magnetization and the frequency-field dependence of two-magnon bound-state excitations, predicted by theory and observed in DTN for the first time. Excellent quantitative agreement with experimental data was obtained.
[1] Phys. Rev. Lett. 98, 047205 (2007).