An effect whereby a material deforms if a magnetic field is applied or whereby a magnetic field is generated if the material is deformed. These materials often contain nickel which exhibits strong magnetostriction.
Magnetostrictive materials (generally laminated) are used in magnetostrictive transducers. Because of eddy currents, magnetostrictive transducers generally have higher loss than piezoelectric transducers, and therefore have greater cooling requirements. However, they are more rugged and can be used at higher temperatures.