Magnetostrictive Materials

AbstractMagnetostrictive materials are a class of smart materials that can convert energy between the magnetic and elastic states. For this reason, magnetostrictive materials and devices based on these materials are often referred to astransducers. Due to the bidirectional nature of this energy exchange, magnetostrictive materials can be employed for both actuation and sensing. Alloys based on the transition metals iron, nickel, and cobalt in combination with certain rare‐earth elements are currently employed in actuator and sensor systems in a broad range of industrial, biomedical, and defense applications. Because magnetostriction is an inherent property of ferromagnetic materials, it does not degrade over time as do some poled piezoelectric substances. In addition, newer magnetostrictive materials provide strains, forces, energy densities, and coupling coefficients that compete favorably with more established technologies such as those based on piezoelectricity. As evidenced by the ever‐increasing number of patented magnetostrictive systems, transducer designers are finding new opportunities to employ magnetostrictive materials in a wide variety of applications ranging from stand‐alone transducers to complex smart structure systems.This article provides an overview of magnetostrictive materials. A description of the physical origin of magnetostriction and a discussion of material behavior are given. A subsequent section is devoted to linear magnetostriction, and other magnetostrictive effects are discussed. Finally, a discussion of current transducer designs and modeling techniques is presented.