Spin-resonance studies
Many
hospitals now use whole-body scanners to look in detail
within the body. These use radio-waves passing through
the body in a strong magnetic field. The radio-waves can
change the spin of a nucleus, with the required
radio-wave frequency depending on the environment of the
atom and the applied magnetic field. Researchers here
use similar techniques to probe the physics of materials,
using both the spin of nuclei and electrons (nuclear magnetic
resonance and electron spin resonance). New magnetic materials,
thin-film magnets, superconductors, metal-insulator transitions,
polymer electrolytes, and a range of biological samples
are all being explored with these techniques.
Some of these experiments are carried out at a few thousandths of a degree above absolute zero, using a helium refrigerator, pictured here. Other researchers are using mm-waves incident on samples in a high magnetic field to explore the structure of matter.
27.7.05
