Dynamic consequences of exchange enhanced anisotropy in ferromagnet/antiferromagnet bilayers

¹ School of Physics, University of Western Australia - 35 Stirling Highway Crawley WA 6009, Australia
² Theoretische Physik, Universität Duisburg-Essen - 47048 Duisburg, Germany

Received: 30 November 2005
Accepted: 3 March 2006

Abstract

The phenomenon of exchange anisotropy is well known in terms of static magnetization properties such as enhanced coercivity and magnetization loop shifts. These effects are primarily associated with effective anisotropies introduced into a ferromagnet by exchange coupling with a strongly anisotropic antiferromagnet. These effective anisotropies can be understood as manifestations of a more fundamental exchange-induced susceptibility. We show that a consequence of this view is that a class of unusual dynamic effects associated with the exchange susceptibility should also exist. The effects become apparent near the ordering temperature of the antiferromagnet and affect domain wall velocities, domain wall resonances, and precessional switching of the ferromagnet.