Effects of Ge substitution for Sn on the crystal structure, magnetization, and the magnetocaloric effect of Mn3SnC

•The Ge substitution for 50% Sn enlarges the magnetovolume effect in Mn3SnC.•The Ge substitution increases high field magnetization at Curie temperature.•The Ge substitution reduces the magnetocaloric effect.•The Ge substitution perhaps causes a change of the electronic structure.