Robust switching of swirls for coupled ferromagnetic nanobricks with the Landau structure

Two magnetic configurations, found by micromagnetic calculations, for a pair of magnetostatically coupled iron nanobricks lower the energy barrier for switching the positions of the swirls on their surfaces using gradient magnetic fields from currents through or near the nanobricks. The advantageous properties of the pairs of nanobricks can be engineered by varying the gap between the vertically stacked pair.