  We report a comprehensive study on the magnetic and structural properties of
the spinel sulfides LiInCr4S8, LiGaCr4S8, and CuInCr4S8, where Li+/Cu+ and
Ga3+/In3+ ions form a zinc-blende-type order. On the basis of synchrotron X-ray
diffraction and magnetization data obtained using polycrystalline samples,
these three sulfides are suggested to be breathing pyrochlore magnets with
alternating antiferromagnetic and ferromagnetic interactions on the small and
large tetrahedra, respectively. The measured magnetization processes of the
three sulfides up to 72 T are significantly different. The magnetization curves
of LiInCr4S8 and CuInCr4S8 have large hysteresis loops with different shapes,
while there is no hysteresis in that of LiGaCr4S8. Geometrical frustration of
the small tetrahedron is likely to give rise to a wide variety of ground
states, indicating the rich physics in these antiferromagnetic-ferromagnetic
breathing pyrochlore magnets.
