magnetoelastischen

Magnetoelasticity, or the magnetoelastic effect, refers to the coupling between magnetic order and the elastic lattice in certain materials. The effect encompasses magnetostriction, where magnetic fields induce mechanical strain, and the inverse or Villari effect, where mechanical stress or strain alters magnetic properties. In ferromagnetic materials, the alignment of magnetic domains with an applied field changes lattice parameters through spin–lattice coupling, producing measurable elongation or contraction. Conversely, applied stress can modify magnetic anisotropy and influence magnetization, switching behavior, or resonance conditions.

Historically, magnetostriction was first observed in iron by James Joule in the 1840s, and the reciprocal effect was described by Luigi Villari in the 1860s. The phenomenon is exploited in modern devices using magnetostrictive materials, which can exhibit substantial strains for practical magnetic fields. The strength of the effect depends on material composition, temperature, and microstructure, as well as on the direction of stress relative to magnetic easy axes.

Materials known for strong magnetoelastic responses include iron-based alloys and specialized magnetostrictive compounds such as Terfenol-D (TbDyFe), Galfenol (Fe-Ga), and METGLAS-based systems. These materials offer large strains, high coupling, and tunable anisotropy, which are valuable for sensors, actuators, and transducers. Applications span precision position sensing, torque or force measurement, vibration damping, sonar and underwater transducers, and energy harvesting. In microelectromechanical systems, magnetoelastic effects enable magnetic field sensing and actuation without complex wiring.

In theory, the magnetoelastic energy arises from the interaction between strain and magnetic order, influencing magnetic anisotropy and domain structure. This coupling is described by magnetostriction constants and elastic moduli, which determine the magnitude of strain under field and the sensitivity to stress.