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The Lagally group is able to use the Synchrotron
Radiation Center to explore the behavior of magnetic materials,
among a multitude of other possibilities for research. The beamline
at the SRC ranges from soft UV to x-rays. X-ray scattering techniques
are used to study magnetic thin films and multilayers. Of special
interest are multilayers which exhibit giant magnetoresistance
(GMR). GMR read heads promise to increase magnetic storage density,
as well as the speed at which data is read. A hot topic of GMR
research is the effect of roughness on the interlayer exchange
coupling. Roughness may have a dramatic effect on the GMR effect
in magnetic multilayers. Using diffuse x-ray resonant magnetic
scattering (DXRMS), we can probe the roughness of surfaces and
buried interfaces. Thus the effect of morphology on these films
can be studied.
Other ongoing research involves the study of magnetic thin
films using the magneto-optical Kerr effect (MOKE). In this
technique, samples are subjected to a variable, externally
applied field. The magnetization of the sample changes with
the applied field, and these changes may be detected by examining
the polarization of light being reflected from the sample.
The shift in polarization angle caused by a magnetic sample
is the MOKE effect. Specifically, MOKE is being used to study
Co grown onto Cu. The Co is grown in the shape of a wedge,
and each wedge is given a different surface roughness. Thus
the magnetic properties of the sample (e.g. coercive field)
can be compared by film thickness and surface roughness.
A new multi-user UHV growth chamber is being added to the
synchrotron, which will also house an in-situ MOKE chamber.
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