Why are magnetostrictive transducers often used at lower ultrasonic frequencies?

Magnetostrictive transducers are primarily utilized in lower ultrasonic frequency ranges due to the physical nature of the magnetostriction process. In these devices, an oscillating magnetic field causes the atoms within a ferromagnetic material—such as iron or nickel—to compress, resulting in periodic changes in the material's length and the generation of mechanical vibrations.12

Because this mechanism relies on the physical deformation of bulk magnetic material, it is less efficient or practical for the extremely high-frequency oscillations that can be achieved by piezoelectric transducers. Consequently, magnetostrictive devices are most commonly employed in industrial applications that operate at lower frequencies, such as ultrasonic cleaning and ultrasonic machining.1