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A NIST technique makes electron spin resonance useful for exploring tiny objects for the
first time.
The team’s electron spin resonance
(ESR) probe takes a large-scale tech-
nique used for decades as a way to
explore bulk materials properties and
for the first time makes it useful for
investigating tiny objects or specific
areas. The new probe is expected to
have a broad range of applications in
fields ranging from chemistry to semi-
conductor design and manufacturing.
“Our new approach brings more
than 20,000 times improvement in
sensitivity over conventional ESR and
allows for investigation of all sorts of
samples that were never thought possi-
ble,” says Jason Campbell.
ESR is widely used in chemistry
and biology research because it can
reveal howmolecules stick together. It is
also used in anthropology, fuel science,
physiology, and meteorology. But the
technique’s sensitivity limits relegate
it to analyzing materials in bulk, with
this limitation stemming from the need
to place samples into a small resonant
chamber. The new approach removes
the resonant chamber entirely. Instead,
microwave energy is introduced by forc-
ing a high-frequency current through a
microscopic wire, which acts as a tooth-
like probe tip that can be moved within
a few micrometers of the sample mate-
rial. Using this approach, specific points
on a surface can be examined. .