Nanosized versions of one of the oldest navigational instruments
known -- a magnetite compass needle -- have been built by Frank
Osterloh, associate professor of chemistry at UC Davis and graduate
student Jin Young Kim. Particles of magnetite (iron oxide) were
strung on nanowires of lithium molybdenum selenide to create magnetic
needles about 400 nanometers long and 30 across. The structures are
so small that they are effectively one-dimensional. Because they are
magnetic, they could be used in devices for measuring magnetic fields
or for making patterns on surfaces, Osterloh said. They are similar
(although smaller) to structures created by some bacteria that use
magnetic fields to orient themselves.
Osterloh and Kim have used similar approaches to build
two-dimensional arrays of cadmium selenide nanoparticles, or "quantum
dots," on surfaces. Arranging and stacking these quantum dots in
different ways changes their optical and light-emitting properties,
Osterloh said. These arrays could be used as waveguides or lasers.
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Contact: Frank Osterloh, Chemistry, (530) 754-6242,
osterloh@chem.ucdavis.edu
Paper: Bottom-up assembly and properties of one- and two-dimensional
magnetic and photoluminescent nanostructures
Authors: Frank E. Osterloh and Jin Y. Kim, Department of Chemistry,
UC Davis
Session: Nanoscience
Session date and time: 8:30 a.m. to 12:30 p.m., Thursday, April 1
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