  The physical properties of the spinel LiGaCr4S8 have been studied with
neutron diffraction, X-ray diffraction, magnetic susceptibility and heat
capacity measurements. The neutron diffraction and synchrotron X-ray
diffraction data reveal negative thermal expansion (NTE) below 111(4) K. The
magnetic susceptibility deviates from Curie-Weiss behavior with the onset of
NTE. At low temperature a broad peak in the magnetic susceptibility at 10.3(3)
K is accompanied by the return of normal thermal expansion. First principles
calculations find a strong coupling between the lattice and the simulated
magnetic ground state. These results indicate strong magnetoelastic coupling in
LiGaCr4S8.
