Magnetoelectric couplings in high-density array of nanoscale Co/BiFeO3 multiferroic heterostructures

We have systematically explored the magnetoelectric (ME) coupling effect of Co/BiFeO3 multiferroic heterostructured nanodot arrays, fabricated by the anodic aluminum oxide template method. Piezoresponse hysteresis loops of these nanodots demonstrate a significant enhancement of the ME coupling effect. More intriguingly, we have realized a magnetic domain transformation from an initial single-domain state to a vortex state by applying a regional or local voltage, and the single-domain state can be recovered by using an external in-plane magnetic field. Our results will guide the invention of high-density, energy-efficient, non-volatile multifunctional ME microdevices.