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arXiv · 0802.0352

Spin Dynamics of $Ni Cl_2-4SC(NH_2)_2$ in the Field-Induced Ordered Phase

S. A. Zvyagin·J. Wosnitza·A. K. Kolezhuk·V. S. Zapf·M. Jaime·A. Paduan-Filho·V. N. Glazkov·S. S. Sosin·A. I. Smirnov
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Abstract

$Ni Cl_2$-$4SC(NH_2)_2$ (known as DTN) is a spin-1 material with a strong single-ion anisotropy that is regarded as a new candidate for Bose-Einstein condensation (BEC) of spin degrees of freedom. We present a systematic study of the low-energy excitation spectrum of DTN in the field-induced magnetically ordered phase by means of high-field electron spin resonance measurements at temperatures down to 0.45 K. We argue that two gapped modes observed in the experiment can be consistently interpreted within a four-sublattice antiferromagnet model with a finite interaction between two tetragonal subsystems and unbroken axial symmetry. The latter is crucial for the interpretation of the field-induced ordering in DTN in terms of BEC.

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S. A. Zvyagin, J. Wosnitza, A. K. Kolezhuk, V. S. Zapf, M. Jaime, A. Paduan-Filho, V. N. Glazkov, S. S. Sosin, A. I. Smirnov. 2008-02-04. Spin Dynamics of $Ni Cl_2-4SC(NH_2)_2$ in the Field-Induced Ordered Phase. https://doi.org/10.1103/physrevb.77.092413

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