  We report thermal expansion and magnetostriction in breathing pyrochlore
magnets LiACr$_4$X$_8$ (A = Ga, In, X = O, S) measured by a dilatometric method
on sintered samples. All four of these compounds showed a large volume
contraction associated with antiferromagnetic order with decreasing
temperature. Above the Ne\'el temperature, LiGaCr4S8 showed negative thermal
expansion, LiInCr4O8 showed positive thermal expansion with concave-downward
temperature dependence, and LiInCr4S8 showed positive forced volume
magnetostriction. All these phenomena are likely caused by the complex
structure-magnetism correlation within the breathing pyrochlore structure with
J and J'. These results suggested that breathing pyrochlore magnets are
promising for the realization of various volumetric phenomena related to their
magnetism not only in the magnetically-ordered phase but also in the
paramagnetic phase.
