We present the results of a combined 7Li NMR and diffraction study on LiGa0.95In0.05Cr4O8, a member of LiGa1−xInxCr4O8 "breathing" pyrochlore family. Via specific heat and NMR measurements, we find that the complex sequence of first-order transitions observed for x=0 is replaced by a single, apparently second-order transition at Tf=11 K. Neutron and X-ray diffraction rule out both structural symmetry lowering and magnetic long-range order as the origin of this transition. Instead, reverse Monte Carlo fitting of the magnetic diffuse scattering indicates that the low temperature phase may be described as a collinear spin nematic state, characterized by a quadrupolar order parameter. This state also shows signs of short range order between collinear spin arrangements on tetrahedra, revealed by mapping the reverse Monte Carlo spin configurations onto a three-state color model describing the manifold of nematic states.
@article{arxiv.1706.08409,
title = {Classical Spin Nematic Transition in LiGa$_{0.95}$In$_{0.05}$Cr$_4$O$_8$},
author = {R. Wawrzyńczak and Y. Tanaka and M. Yoshida and Y. Okamoto and P. Manuel and N. Casati and Z. Hiroi and M. Takigawa and G. J. Nilsen},
journal= {arXiv preprint arXiv:1706.08409},
year = {2017}
}