Abstract:
Conventional approaches for imaging magnetic fields are limited to investigating the surface of a sample and the free space aroung it; the observation of the spatial distribution of magnetic fields within a bulk sample is not possible. In order to overcome this problem, a new imaging technique has recently been proposed by a group of researchers at the Hahn-Meitner-Institute (HMI), Berlin, Germany. This new method uses neutrons, subatomic particles whose zero net electrical charge allows them to penetrate thick layers of matter, but whose intrinsic magnetic moment makes them highly sensitive to magnetic fields. Utilizing the magnetic interaction of a spin-polarized neutron beam, it is possible to visualize magnetic fields both in free space and in the bulk of solid, massive, opaque samples, revealing the field line distribution both in two and three dimensions.