The Magnetostrictive Material node is obsolete and will be removed in future versions. It cannot be added in version 6.1 and later, but may be present in models created by earlier versions of the software.

You are advised to update your model to use one of the new multiphysics interfaces instead, either The Nonlinear Magnetostriction Interface or The Piezomagnetism Interface (for modeling linear magnetostrictive effects).