Eur. Phys. J. B 27, 103-109 (2002)
https://doi.org/10.1140/epjb/e20020134

Dipolar coupling effect in magnetic bilayer system

¹ Laboratoire PMTM; CNRS - Université Paris-13, 93430 Villetaneuse, France
² Laboratoire de Magnétisme et d'Optique, CNRS-Université de Versailles, St. Quentin en Yvelines, 78035 Versailles, France

Corresponding author: ^a ml@lpmtm.univ-paris13.fr

Received: 12 December 2001
Published online: 15 May 2002

Abstract

Equilibrium micromagnetic structures in a bilayer system composed of two thin cobalt films separated by a non magnetic spacer are systematically analysed. These 2D magnetization distributions are obtained by numerical computations according to different set of magnetic and geometric parameters. The coupling effect due to the dipolar long range interaction (or stray-field effect) between the two Co layers is studied through the evolution of the magnetic pattern in the stack with or without an applied field and compared to a continuous film of same thickness. Special attention is paid to the hysteresis process in a bilayer. Even though the general aspect of the magnetization distribution looks like a Landau-Lifshitz structure, the absence of any core in the vortex of the magnetic structure is analysed in relation to a possible disappearence of (topological) hysteresis.