Neutron reflectometry on magnetic thin films

The current interest in the magnetism of ultrathin films is driven by their manifold applications in the nano-technology area, for instance as magneti c field sensors or as devices for information storage. Neutron scattering h as played a dominant role for the determination of spin structures, phase t ransitions, and magnetic excitations in bulk materials. Today, its potentia l for the investigation of thin magnetic films has to be redefined. In the field of thin film magnetism, polarized neutron reflectivity (PNR) at small wave vectors can provide precise information on magnetization vectors in t he film plane and on their variation from plane to plane. Therefore, neutro n scattering remains the only method which allows to unravel the magnetizat ion in thin films and superlattices independent of their thickness and dept h below the surface. In addition, PNR is not only sensitive to structural i nterface roughness but also to the magnetic roughness. Some new development s will be discussed. (C) 2000 Elsevier Science B.V. All rights reserved.