Magnetic Excitations in the Spin-1 Anisotropic Heisenberg Antiferromagnetic Chain System NiCl2-4SC(NH2)2


Magnetic Excitations in the Spin-1 Anisotropic Heisenberg Antiferromagnetic Chain System NiCl2-4SC(NH2)2

Zvyagin, S. A.; Wosnitza, J.; Batista, C. D.; Tsukamoto, M.; Kawashima, N.; Krzystek, J.; Zapf, V. S.; Jaime, M.; Oliveira, N. F. J.; Paduan-Filho, A.

NiCl2-4SC(NH2)2 (DTN) is a quantum S = 1 chain system with strong easy-pane anisotropy and a new candidate for the Bose-Einstein condensation of the spin degrees of freedom. ESR studies of magnetic excitations in DTN in fields up to 25 T are presented. Based on analysis of the single-magnon excitation mode in the high-field spin-polarized phase and previous experimental results [Phys. Rev. Lett. 96, 077204 (2006)], a revised set of spin-Hamiltonian parameters is obtained. Our results yield D = 8:9 K, Jc = 2:2 K, and Ja;b = 0:18 K for the anisotropy, intrachain, and interchain exchange interactions, respectively. These values are used to calculate the antiferromagnetic phase boundary, 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 is obtained.

  • Physical Review Letters 98(2007), 047205

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Publ.-Id: 9399