ALSNews is a biweekly electronic newsletter to keep users and other interested parties informed about developments at the Advanced Light Source, a national user facility located at Lawrence Berkeley National Laboratory, University of California. We welcome suggestions for topics and content.
Previous Issues are available.
The pressure on the magnetic data storage industry to pack more information into smaller volumes has pushed the study of thin magnetic films to the quantum level. Investigations into the properties of magnetic materials at the nanostructure scale have revealed that, when two layers of ferromagnetic material are separated by a thin nonmagnetic spacer, the relative spin directions of the ferromagnetic layers oscillate as a function of the spacer thickness. Pioneering photoemission experiments at other facilities have shown that this oscillation is associated with quantum well state effects in the spacer. New work at the ALS using wedge-shaped samples has revealed additional, more subtle interference effects. According to the quantum well states model, when the thickness of the spacer is reduced to a few nanometers, the continuum of electron states normally available becomes quantized into discrete energy levels.