arXiv:2001.08555 · Physical review. B./Physical review. B
Inelastic neutron scattering study of the anisotropic S=1 spin chain [Ni(HF2)(3−Clpyridine)4]BF4
Daniel M. Pajerowski, Jamie L. Manson, J. Herbrych, Jesper Bendix, Andrey A. Podlesnyak, John M. Cain, Mark W. Meisel
Abstract
$[\mathrm{Ni}({\mathrm{HF}}_{2})(3\ensuremath{-}\text{Clpyridine}){}_{4}]{\mathrm{BF}}_{4}$ (NBCT) is a one-dimensional, $S=1$ spin chain material that shows no magnetic neutron Bragg peaks down to temperatures of 0.1 K. Previous work identified NBCT as being in the Haldane phase and near a quantum phase transition as a function of $D/J$ to the large-$D$ quantum paramagnet phase (QPM), where $D$ is the axial single-ion anisotropy and $J$ is the intrachain superexchange. Herein, inelastic neutron scattering results are presented on partially deuterated, $^{11}\mathrm{B}$-enriched NBCT polycrystalline samples in zero magnetic field and down to temperatures of 0.3 K. Comparison to density matrix renormalization group calculations yields $D/J=1.51$ and a significant rhombic single-ion anisotropy $E$ ($E/D\ensuremath{\approx}0.03, E/J\ensuremath{\approx}0.05$). These $D, J$, and $E$ values place NBCT in the large-$D$ QPM phase but precipitously near a quantum phase transition to a long-range ordered phase.