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arXiv · 1501.03226

Suppression of 3D-ordering by defects in the $S=1/2$ frustrated chain magnet LiCuVO$_4$

L. A. Prozorova·S. S. Sosin·L. E. Svistov·N. Buettgen·J. B. Kemper·A. P. Reyes·S. Riggs·O. A. Petrenko·A. Prokofiev
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Abstract

We report on a heat capacity study of high quality single crystal samples of \lcvo\ -- a frustrated spin $S=1/2$ chain system -- in magnetic field amounting to 3/4 of the saturation field. At low fields up to about 7~T, a linear temperature dependence of the specific heat, $C_p\propto T$, resulting from 1D magnetic correlations in the spin chains is followed upon cooling by a sharp lambda anomaly of the transition into a 3D helical phase with $C_p\propto T^3$ behavior at low temperature. The transition from a spin liquid into a spin-modulated (SM) phase at higher fields occurs via a hump-like anomaly which, as the temperature decreases further turns into a $C_p\propto T^2$ law distinctive for a quasi-2D system. We suggest an explanation for how nonmagnetic defects in the Cu$^{2+}$ chains can suppress 3D long-range ordering in the SM phase and leave it undisturbed in a helical phase.

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L. A. Prozorova, S. S. Sosin, L. E. Svistov, N. Buettgen, J. B. Kemper, A. P. Reyes, S. Riggs, O. A. Petrenko, A. Prokofiev. 2015-01-14. Suppression of 3D-ordering by defects in the $S=1/2$ frustrated chain magnet LiCuVO$_4$. https://arxiv.org/abs/1501.03226

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