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arXiv · 1411.6075

Two-step antiferromagnetic transition and moderate triangular frustration in Li2Co(WO4)2

I. Panneer Muthuselvam·R. Sankar·A. V. Ushakov·G. Narsinga Rao·Sergey V. Streltsov·F. C. Chou
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Abstract

We present a detailed investigation of the magnetic properties of the spin-$\frac{3}{2}$ system Li$_2$Co(WO$_4$)$_2$ by means of magnetic susceptibility and specific heat. Our experimental results show that in Li$_2$Co(WO$_4$)$_2$ a short-range antiferromagnetic (AFM) correlations appear near $χ$$_{max}$ $\sim$ 11 K and two successive long-range AFM phase transitions are observed at T$_{N1}$$\sim$ 9 K and T$_{N2}$$\sim$ 7 K. The frustration factor, $\mid$$Θ$$\mid$/T$_{N1}$$\sim$3, indicates that the system is moderately frustrated, which is identifiable by the broken triangular symmetry within both $ab$- and $bc$-planes for the triclinic crystal structure. The magnetic isotherm at temperatures below T$_{N2}$ shows a field-induced spin-flop transition, and a complete H-T phase diagram for the two-step AFM system is mapped. $Ab$~$initio$ band structure calculations suggest that the strongest exchange coupling does not correspond to the shortest Co-Co distance along the $a$-axis, but rather along the diagonal direction through a Co-O-W-O-Co super-superexchange path within the $bc$-plane

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I. Panneer Muthuselvam, R. Sankar, A. V. Ushakov, G. Narsinga Rao, Sergey V. Streltsov, F. C. Chou. 2014-11-22. Two-step antiferromagnetic transition and moderate triangular frustration in Li2Co(WO4)2. https://arxiv.org/abs/1411.6075

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