We studied the thermal expansion and magnetostriction of polycrystalline samples of GdMn6Sn6 intermetallic compound with hexagonal HfGe6Fe6-type structure in the temperature range of 77–520 K. The thermal expansion measurement of the sample shows anomalous behavior around its TC¼434 K and TM¼309 K, possibly the point of collapse-like reduction of Mn moments. In addition, the isofield curves of anisotropic and volume magnetostriction reveal anomalies around paramagnetic to ferrimagnetic phase transition. The obtained experimental results are discussed in the framework of two-magnetic sublattices by bearing in mind the lattice parameter dependence of interlayer Mn–Mn exchange interaction in this layered compound. From the temperature dependence of magnetostriction values and considering the magnetostriction relation of a hexagonal structure, we attempt to determine the signs of some of the magnetostriction constants as well as a comparison of their orders of magnitude for this compound.

Keywords