Dipolar interaction in dense chains of submicrometric rectangular dots

Abstract

Dense chains of rectangular dots (715×450 nm) put side by side, with interdot spacing variable in the range between about 55 and 625 nm, have been patterned by deep UV lithography, starting from a 40 nm thick permalloy film. A magneto-optical Kerr effect study, assisted by magnetic force microscopy, revealed that the magnetization inversion proceeds through the nucleation and the annihilation of two vortices, with the nucleation and annihilation fields appreciably affected by the coupling. The latter also modifies the frequency of the fundamental resonant mode of precession of the magnetization, measured by Brillouin light scattering from spin-wave. Micromagnetic simulations enabled us to account for the main features observed in the experiment. © 2010 IOP Publishing Ltd.