Condensed Matter Physics Seminar

3 p.m., Monday, November 14, 2005
MRSEC Conference Room, 2202 Physics Building

 Half-Metallic Manganites, Magnetic Domain Walls, and Carbon Nanotubes

Luis E. Hueso

(Department of Materials Science, University of Cambridge, UK)

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.

Host:  Maria Calderon
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