Switching asymmetries in closely coupled magnetic nanostructure arrays

Cobalt nanostructures (220 and 300 nmx275 nmx30 nm) were fabricated using e lectron beam lithography into ordered, close proximity (170 nm) arrays. Dom ain configurations with accompanying hysteresis loops were measured using o ff-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 f ield relative to the in-plane hysteresis-field direction. (C) 1999 American Institute of Physics. [S0003-6951(99)05543-6].