UNIVERSITY OF SOUTHAMPTON
ABSTRACT
FACULTY OF SCIENCE
DEPARTMENT OF PHYSICS AND ASTRONOMY
Doctor of Philosophy
ENGINEERING THE MAGNETIC PROPERTIES OF
EPITAXIAL RE-Fe2 LAVES PHASE ALLOY AND
MULTILAYER FILMS
by Jean-Marc L. Beaujour
Epitaxial Laves phase based alloy and multilayer films grown by molecular beam epitaxy enable the study of the influence of epitaxial strain upon the magnetic
properties of the materials. In particular, the temperature dependence of
anisotropy constant of highly magnetostrictive materials such as DyFe2 and TbFe2
synthesized on a substrate is the signature of the built-in epitaxial strain
effect.
The magnetisation reversal mechanism in DyFe2 – YFe2 multilayer and DyFe2 /
TbFe2 alloy films can be described by the principle of coherent rotation.
However, in the case of DyFe2 – YFe2 multilayer films, if the YFe2 layer is
sufficiently thick, the interfacial interaction give rise to the formation of
magnetic exchange springs in the YFe2 layer.
The DyFe2 – YFe2 superlattices form convenient model systems to study the effect
of magnetic exchange springs, since the relative thickness of the DyFe2 and YFe2
layers are readily controlled in the growth process. Moreover, the magnetic
exchange springs can be tailored to engineer novel magnetic phases such as
negative coercivity, and magnetic compensation points.