Sometimes chance leads
to discoveries. Developed last year by Chicago and Argonne National Laboratory
researchers, silver chalcogenide sensors (pictured below) can measure magnetic
fields up to 600,000 Gauss strong, or more than 1 million times the Earth's magnetic
field. The team originally was studying the effect of electrical charges on silver
selenide, says research leader Thomas Rosenbaum, the James Franck professor of
physics. When below-room-temperature tests produced "strange" results,
the researchers applied a magnetic field to the selenide compound in an attempt
to understand the phenomenon. Instead they discovered the material's unexpected
sensitivity to magnetic fields. Rosenbaum calls it "a classic case of serendipity."
exceptionally accurate sensors-each measuring 1 cubic millimeter and costing a
few cents to produce-can be used in medical exams, such as magnetic resonance
imaging, and in computing technology, such as high-temperature superconductors.