Introduction

We do basic research on magnetic properties of materials at reduced dimensionality. This includes magnetic surfaces, thin films, wires and dots with linear scales of 1 to 1,000 atoms. We are particularly interested in the correlation between structural properties and growth modes of these structures on the one hand, and their magnetic, electronic, and mechanical properties on the other hand.

Thin films are grown by molecular beam epitaxy and/or laser ablation. Magnetic wires and dots are made by using specially structured substrates for molecular beam epitaxy. Surface structures are analyzed by surface X-ray diffraction, scanning tunneling microscopy, and low energy electron diffraction. Magnetic properties of surfaces, interfaces, and magnetic nanostructures are analyzed by spin-polarized low energy electron scattering, spin-polarized scanning tunneling microscopy and by photoemission with femtosecond lasers. The magneto-optic Kerr effect serves as a transfer standard between different experiments.

Our present interests also include oxides, either as ferromagnets in their own right or as insulating films in spin-polarized tunneling devices for magnetoelectronics applications. We are currently exploring experimental ways to reveal electron correlation effects by means of coincidence spectroscopy.

Since March 2003 we have an intense and fruitful cooperation with the Laboratoire Louis Néel, Grenoble, within the framework of a "Joint European Laboratory" (Laboratoire Européen Associé). This includes regular meetings at Grenoble or Halle as well as exchange of personnel lasting from a few weeks to one year.