Polarized neutron channeling in weakly magnetic films

Abstract

We describe a new sensitive method for the investigation of weakly magnetic films placed inside a tri-layer planar waveguide. Polarized neutrons tunnel into the waveguide through the surface, channel along the layers and are emitted from the end face as a narrow and slightly divergent microbeam. Polarization analysis permits to detect very small magnetization in the order of a few 10 Gauss. The magnetic film containing the rare-earth element Tb was investigated using both fixed wavelength and time-of-flight polarized neutron reflectometers. The experimental results are presented and discussed.

Divergence of neutron microbeams from planar waveguides

“…In the experiment, the length of the waveguide was 25 mm. The sample selects the incident beam of width At the NREX reflectometer, a neutron microbeam intensity 10 n/s for a neutron wavelength 4.26 Å was sufficient to use the polarized neutron channeling method for the investigation of the weakly magnetic films of TbCo 5 [16] and TbCo 11 [55]. Thus we have demonstrated the feasibility of polarized neutron microbeam applications for the investigations of magnetic nanostructures at fixed wavelength reflectometers.…”

Channeling of Neutrons in a Nonmagnetic Planar Waveguide

“…In [39] the calculations were done for the simple waveguide with a weakly magnetic film as a middle layer. In [40,41] using PNC the weakly magnetic films containing rare-earth elements were investigated. Such films are broadly used for the development of new methods of magnetic recording and switching [42].…”