Magnetostrictive materials are materials that exhibit a strain when exposed to a magnetic field. In other words, magnetostrictive materials undergo a deformation when a magnetic field is present. These materials are referred to as the Rare-Earth's. Rare-Earth materials typically consist of the lanthanides group in the transition metals on the periodic table.
The difference between traditional magnetostrictive materials as opposed to giant magnetostrictive materials is the amount of strain per unit volume of the material. Giant magnetostrictive materials are materials that undergo large amounts of strain (i.e., large deformations) for a given applied magnetic field. One such material in the giant magnetostriction category is TERFENOL-D. TERFENOL-D is a proprietary alloy consisting of terbium, dysprosium, and iron in varying compositions.
Some of the recent developments surrounding magnetostrictive applications include solid state speakers, vibration “shake” tables, transducers, various types of sensors, and actuators. Magnetostrictive devices show potential for replacing traditionally piezoelectric devices as well. This last claim comes from the fact that magnetostriction is a material property that does not decay over time—experience less hysterisis Furthermore, a magnetostrictive device is fairly robust as far as wear and tear are concerned. Recent reports suggest that TERFENOL-D based actuators and sensors exposed to overheating will experience problems, however after the material is brought back to reasonable temperatures it will be functional once more. This is in contrast to some traditional materials that are ruined after an overheating event.