Organisers

• Walter Temmerman (Daresbury)
• James Tobin (Lawrence Livermore National Laboratory)
• Gerrit van der Laan (Daresbury Laboratory)

Supports

 CECAM

 Psi-k

Description

This International Workshop on Orbital and Spin Magnetism of Actinides (IWOSMA) is the third in a series. The first
workshop took place in Daresbury in 1999 and the second in Berkeley, CA, USA in
2002. These workshops are informal gatherings of theoreticians and experimentalists
addressing the latest issues in the electronic and magnetic properties of actinides.

Scientific Objectives

The magnetism of transition metal systems and lanthanide systems is now fairly well
understood, where d and f electrons can be described in a delocalized and localized
model, respectively. On the other hand, actinide systems do not fit in such a
description. The localization of the 5f is in between that of the 3d and 4f and the
strong spin-orbit interaction necessitates a relativistic approach. Furthermore, electron
correlation effects play a major role in these compounds. Recently, it has become
possible to determine element-specific magnetic moments using neutron diffraction
and x-ray scattering and absorption. The latter technique makes it even possible to
separate the orbital and spin contribution to the total magnetic moment. The results
are very interesting but difficult to reproduce with present state-of-art calculations.
Not only a very large orbital polarization but also a large magnetic dipole term has
been measured in cubic compounds, such as US. This allows for severe testing of the
extra terms included in band theory to account for orbital polarization. It is also clear
that deeper insight in magnetism can be obtained by studying the unusual behaviour
of the actinides. The recent development and application of such techniques as DMFT
could contribute to the understanding of magnetism in actinides. Despite the fact that
actinides for health reasons will find less application in technological market
products, the understanding of their magnetic and electronic properties will no doubt
provide key elements for a general description of electron correlation and relativistic
effects.