Manipulation of magnetic vortex cores in planar magnetic materials using a voltage induced strain

The present work studies the effects of inducing a strain gradient on micron-sized Galfenol and nickel devices containing vortex cores by means of a piezoelectric element. Micromagnetic simulations show that the strain induced anisotropy gradient causes vortex core translation along the direction of the gradient, which is key to efficient excitation of the core dynamics. The effect of the strain gradient symmetry on the displacement of the core is investigated and the experimental implementation of the strain gradient is also discussed. For the latter, two approaches are considered. The first is to make use of the ferroelastic multi-domain state of a ferroelectric substrate. The second is based on tailoring a gradient in the strain by patterning two electrodes on top of the piezoelectric substrate.