Studies of coupling and ordering in magnetic thin films
Suzanne te Velthuis
Argonne National Lab
Abstract
Traditionally neutron scattering has been an important tool for studying
bulk magnetic materials. The success has been due to the high
sensitivity of neutrons for magnetic moments, combined with their
characteristics in relationship to wavelength and velocity. As the
interest of the scientific community has shifted towards nanostructured
materials, polarized neutron reflectivity (PNR) and scattering at
grazing incidence have emerged as powerful methods for studying magnetic
thin films.
As will be illustrated by the presentation of several experiments, the
depth dependent magnitude and orientation of the magnetization in a thin
film can be determined with PNR. In the case of GaMnAs thin films
knowledge about the magnitude of the magnetization provided
understanding about the effect of temperature annealing in these films.
Determination of the orientation of the magnetization of individual Fe
layers in Fe/Cr[110] superlattices as was essential to the understanding
of the magnetic coupling between the Fe layers spaced by Cr. Finally,
PNR experiments performed with polarization analysis mapped out the
evolution of individual magnetization vectors during the first order
spin flop transition in a finite antiferromagnet, thereby confirming
theoretical predictions about this magnetic phase transition.
This work is supported by US DOE, Office of Science contract
#W-31-109-ENG-38.