Magnetic excitations in the spin-1 anisotropic Heisenberg antiferromagnetic chain system NiCl(2)-4SC(NH(2))(2)

• Published in: Physical review letters Vol. 98; no. 4; p. 047205
• Main Authors: Zvyagin, S A, Wosnitza, J, Batista, C D, Tsukamoto, M, Kawashima, N, Krzystek, J, Zapf, V S, Jaime, M, Oliveira, Jr, N F, Paduan-Filho, A
• Format: Journal Article
• Language: English
• Published: United States 26.01.2007
• ISSN: 0031-9007

NiCl(2)-4SC(NH(2))(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)10.1103/PhysRevLett.96.077204], a revised set of spin-Hamiltonian parameters is obtained. Our results yield D=8.9 K, J(c) = 2.2 K, and J(a,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.