Anomalous Hall effect studied via guided vortex motion

The anomalous Hall effect is examined using guided vortex motion in patterned high-T-c superconducting thin films. Rows of micrometer holes (antidots) affect the direction of flux motion in Hall arrangements. This allows to distinguish between different contributions to the Hall signal. We demonstrate, that the anomalous Hall effect is not caused by normal charge carriers, but rather by vortex motion antiparallel to the applied current. This is demonstrated by the suppression of the anomalous Hall effect in the case of guidance of vortices perfectly perpendicular to the applied current. It is concluded that the Magnus force being a force on the vortices that would contain a transverse component might be responsible for the anomalous Hall effect. (c) 2005 Elsevier B.V. All rights reserved

Polyoxometalates: building blocks for functional nanoscale systems

Polyoxometalates (POMs) are a subset of metal oxides that represent a diverse range of molecular clusters with an almost unmatched range of physical properties and the ability to form dynamic structures that can range in size from the nano- to the micrometer scale. Herein we present the very latest developments from synthesis to structure and function of POMs. We discuss the possibilities of creating highly sophisticated functional hierarchical systems with multiple, interdependent, functionalities along with a critical analysis that allows the non-specialist to learn the salient features. We propose and present a "periodic table of polyoxometalate building blocks". We also highlight some of the current issues and challenges that need to be addressed to work towards the design of functional systems based upon POM building blocks and look ahead to possible emerging application areas