The influence of weak links on magnetic ordering in layered structures

¹  Department of Physics, Uppsala University - Box 530, 751 21 Uppsala, Sweden
²  Russian Federal Nuclear Center VNIIEF - 37, Mira str., Sarov, 607188, Russia
³  Institut für Experimentalphysik/Festkörperphysik, Ruhr-Universität Bochum - 44780 Bochum, Germany
⁴  Department of Physics, University of Durham - South Road, Durham DH1 3LE, UK
⁵  Department of Engineering Sciences, Uppsala University - Box 534, 751 21 Uppsala, Sweden

Received: 14 July 2007
Accepted: 5 November 2007

Abstract

We discuss the magnetic ordering in layered magnets with two different inherent ordering temperatures. A [V(12 ML)Fe(2 ML)/V(12 ML)(/Fe(3 ML)]₇₀ superlattice with anti- ferromagnetic interlayer exchange coupling is used for this purpose. The more rapid decrease of the magnetic moment in the 2 monolayer thick Fe layers influences the ordering in a non-trivial way. A distribution of the effective ordering temperature is inferred, originating from a more rapid decrease of the magnetic moment in the near-surface region, as compared to the interior of the sample. The results clearly demonstrate the need to consider all energy and length scales when addressing ordering in materials with finite extension.