Intermetallic Magnets: From Itinerant Magnetism to Magnetic
Refrigeration
2010 Seminar Series Presents4:00PM, Monday, December 07, 2009219 Brown Laboratory
Professor Gordon Milleriowa stateUniversity, dePartMent of CheMistry
Magnetism is governed by the behavior of unpaired electrons in materials that typically contain
3d transition metals and 4ƒrare-earth metals. For intermetallic compounds containing 3d
elements, the unpaired electrons are also involved in electronic conduction – so-called itinerant
magnets. Interatomic exchange coupling can lead to ferromagnetic, antiferromagnetic, or other
intermediate types of magnetic order, some of which depend on the number of valence electrons.
When rare-earth metals occur, the 4ƒ electrons are generally localized, and interatomic exchange
coupling occurs via the conduction band involving the valence 5d orbitals of the rare-earth metals.
These interactions can be influenced by chemical composition and valence electron count. This seminar
will summarize some of our recent efforts to study
the relationships among chemical composition,
electronic structure and magnetism in three
different systems:
(a) transition metal gallides, CrGa-MnGa-FeGa;
(b) complex metal-rich borides, Sc2Fe(Ru1–
xRhx)5B2; and (c) rare-earth magnetic refrigerants,
RE5(SixGe1–x)4. The presentation will identify rules
for ferromagnetic or antiferromagnetic order
in 3d itinerant magnets as well as factors
important for magnetic refrigeration
applications.
University of Delaware
Itinerant Magnetism
Fe12 Clusters in FeGa
Giant MCE in Gd5Si2Ge2
FM vs. AFM in Sc2Fe(Ru1−xRhx)5B2
Fe Ladders in Ti9Fe2Ru18B8
Department of
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