One or more layers of magnetostrictive material are arranged to have a meandering current running therethrough or through a closely spaced sheet of conductive material, to provide longitudinal, torsional or flexural modes of mechanical vibration. For torsional vibration a cylindrical structure having a spiral strip either conductive or magnetostrictive, is described. Copper or gold is deposited on the magnetostrictive material. Ladder filters using magnetostrictive structures consist of a thin sheet with a layer of magnetostrictive material thereon suitably cut to provide a number of reeds.