Magnetic structures and magnetization processes in layered systems with antiferromagnetic couplings

Ulrich K. Rößler 1A. N. Bogdanov 1,2

1. Institut fuer Metallische Werkstoffe, IFW, Dresden, Germany
2. Donetsk Institute for Physics and Technology, Donetsk 83114, Ukraine

Abstract

Antiferromagnetic superlattices, layered systems with antiferromagnetic interlayer couplings between different ferromagnetic layers, or ferromagnetic layers pinned to crystalline or synthetic antiferromagnets are typical structures in magnetoelectronic devices.

They can be considered as realizations of artificial antiferromagnetic or ferrimagnetic multi-sublattice structures. Owing to the close competition between intrinsic and induced magnetic anisotropies with interlayer exchange and external fields, these structures display a wide variety of magnetic states. From a basic micromagnetic point of view, we review our understanding of the related magnetization processes.

In particular, we show that most of these systems are characterized by sequences of first-order magnetic transitions in external fields. The importance of the concomitant domain-processes is explained.

We discuss the appearance of spin-flop phases and canted phases in antiferromagnetically coupled bilayers and multilayers, and in multilayer systems

pinned through exchange-bias mechanisms. The role of chiral symmetry breaking and biaxial anisotropy in layered systems is discussed within a general phenomenological theory for surface-induced magnetic interactions.

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Presentation: invited oral at E-MRS Fall Meeting 2005, Symposium D, by Ulrich K. Rößler
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-07-04 21:31
Revised:   2009-06-07 00:44
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