*

LiGaCr₄S₈ is a breathing pyrochlore lattice where the ordering of the Li⁺ and Ga³⁺ cations on the A-site of the spinel structure leads to the periodic expansion and contraction of Cr₄ tetrahedra. Strong magneto-elastic coupling drives negative thermal expansion in the temperature range 12-110 K. Neutron diffraction and inelastic neutron scattering experiments were carried out on polycrystalline samples of LiGaCr₄S₈ to investigate the spin configuration and spin-spin interactions. No long-range magnetic order is observed above 1.5 K. However, neutron diffraction shows the gradual appearance of a magnetic signal centered at |Q|~0.51 Å^-1 on cooling below ~100 K and a second contribution at |Q|~0.64 Å^-1 appears below 15 K. The inelastic neutron scattering data shows spin excitations with a zone boundary energy 12.6 meV at 4 K. The intensity of the inelastic signal weakens above 10 K though persists to nearly 100 K. At low energies the dynamic susceptibility can be described with a single temperature dependent relaxation.