Voltage Tunability of Magnetic Vortex Gyrotropic Mode Frequency in an Elliptical Magnetostrictive Nanodisk

Micromagnetic simulations predict vortex gyrotropic frequency variations induced by voltage-generated uniaxial stress in a soft, elliptical, magnetostrictive nanodisk. The gyrotropic frequency decreases when the direction of uniaxial stress changes from the major axis of the nanodisk to the minor axis, whereas a more notable downshift of the gyrotropic frequency occurs when the magnitude of the stress increases. The mechanism is analyzed in terms of the stiffness coefficients, which are calculated based on the vortex dynamic energy profile. This voltage tunability of gyrotropic frequency paves the way for the realization of vortex oscillators and frequency-controlled vortex computer memory with ultralow power consumption.