| Abstract: | Materials
science has been intensively developed during the last 30 years. This
is due, on the one hand, to
an increasing demand of new materials for new applications and, on the
other hand, to technological
progress which allows for the synthesis of materials of desired
characteristics and to investigate their
properties with sophisticated experimental apparatus. Among these
advanced materials, magnetic ma-terials at nanometric scale such as
ultra thinfilms or ultrafine aggregates are no doubt among the most
important for electronic devices. In this review, we show advanced
theoretical methods and solved examples that help understand microscopic
mechanisms leading to experimental observations in magnetic thin films.
Attention is paid to the case of magnetically frustrated systems in
which two or more magnetic interactions are present and competing. The
interplay between spin frustration and surface effects is the origin of
spectacular
phenomena which often occur at boundaries of phases with different
symmetries: reentrance, disorder
lines, coexistence of order and disorder at equilibrium. These phenomena
are shown and explained using
of some exact methods, the Green's function and Monte Carlo simulation.
We show in particular how to
calculate surface spin-wave modes, surface magnetization, surface
reorientation transition and spin
transport |
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