Frequency Dependence of Magnetic and Magnetoelastic Properties of Magnetostrictive Materials for Multiferroic Antennae

Magnetoelectric (ME) resonators are of significant interest for pure mechanically driven antennae targeting the ULF/VLF radio frequency range. Direct coupling of magnetostrictive and piezoelectric phases in the ME composites enables time variable magnetic field generation with exceptionally low operational power requirements. A dynamic stress loading of the magnetoelastic/magnetostrictive material by piezoelectric element results in a fluctuating magnetic field. In this work we fully characterize magnetostrictive materials Fe_81.6Ga_18.4 and Terfenol-D at high frequencies up to several kHz and studied the effect of eddy current losses that potentially curtail the magnetic response of the material. We evaluated the dynamic response of Galfenol rod up to 1000 Hz comparing both its sensing response (changing dynamic stresses) to its actuation response (changing dynamic magnetic fields) in both solid and laminated rods.