Switching asymmetries in closely coupled magnetic nanostructure arrays

Abstract
Cobalt nanostructures (220 and 300 nm×275 nm×30 nm) were fabricated using electron beam lithography into ordered, close proximity (170 nm) arrays. Domain configurations with accompanying hysteresis loops were measured using off-axis electron holography. Measurements were compared to solutions of the Landau–Lifshitz–Gilbert equations. Both exhibit switching asymmetries due to strong intercell coupling and the presence of a field normal to the cell surface. Magnetic domain configurations during switching depended strongly on the initial conditions, as well as the direction of the perpendicular field relative to the in-plane hysteresis-field direction.