Half-Metallic Manganites, Magnetic Domain Walls and Carbon Nanotubes
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Date: 11-16-2005
Start Time:
4:00pm
End Time: 5:00pm
Speaker: Luis E. Hueso
From:
University of Cambridge, UK
Location: Interschool Lab, 7th floor, Schapiro/CEPSR
Hosted by:
Center for Integrated Science
Abstract:
I will discuss electrical transport between half-metallic manganite
electrodes connected by native domain walls and, more exotically,
carbon nanotubes. Manganites are mixed-valent oxides of manganese that
display interesting physical properties such as “electronic” phase
separation, and metallic phases with almost fully spin polarised
conduction electrons.
Native domain walls. In a phase separated thin film manganite device,
magnetic domain walls can be created in ferromagnetic percolating
pathways. The magnetoresistance of these devices was tested in
different geometries, yielding qualitatively different results.
Moreover, the changes in resistance-area product are large enough to
suggest that the domain walls display mesoscopic phase separation at
the wall centres.
Manganite-carbon nanotube-manganite devices. Ferromagnetic metallic
manganite electrodes connected by a carbon nanotube also display
magnetoresistance. This demonstrates micron-scale spin coherence in the
nanotube, and spin injection between an inorganic half-metallic crystal
and the organic molecule.