S. V. Kozhevnikov

Spin-flip spatial neutron beam splitting in magnetic media

Possible uses of the effect of beam splitting for investigations of magnetic media, formation of neutron beams and measurements of their characteristics are discussed. The results of experimental investigations of magnetic layers and layered structures are presented. The application of the effect for the determination of the parameters of uniformly magnetized magnetics and magnetics with a domain structure is noted as perspective.

Refraction of polarized neutrons in a magnetically non-collinear layer

Abstract The refraction of polarized neutrons in a magnetic layer in relation to the neutron wavelength, the magnitude and direction of an external magnetic field, has been investigated experimentally. The effects of space splitting of the polarized neutron beam and the interference of neutron beams with different spin states have been observed and measured.

Application of a Polarized Neutron Microbeam to the Investigation of a Magnetic Microstructure

The application of a neutron microbeam to the investigation of an internal magnetic microstructure has been demonstrated experimentally. The object of investigation is an amorphous magnetic wire 190 μm in diameter, with the axial and circular magnetic domains formed inside it. A narrow neutron microbeam with a width of 2.6 μm, which is formed by a three-layer film (a planar waveguide) serves as the probe for scanning with a high spatial resolution. The method of investigation is the neutron spin precession upon transmission through the sample.

System of neutron microbeams from a planar waveguide

Results of experimental investigations of space, angular and wavelength distribution in neutron microbeams obtained for the first time with the help of a resonant planar neutron waveguide at the time-of-flight reflectometer of the IBR-2 pulsed reactor are reported and comparison with theoretical calculations is presented. Possible application of microbeams in physical experiments is discussed.

Data representations of Zeeman spatial beam splitting in polarized neutron reflectometry

The different Zeeman beam-splitting effects in neutron reflectivity experiments in reflection and refraction are discussed. Different possible representations of the experimental Zeeman splitting data in various coordinate systems are investigated. Some of these representations are useful to unambiguously identify the off-specular splitting arising from Zeeman energy and discriminate it from the usual diffuse scattering. Some representations are more suited for the direct extraction of quantitative information about the systems by using the Zeeman splitting effect. The Zeeman splitting can thus be used as a tool rather than being treated as a parasitic effect. Parameters such as the optical and magnetic potentials of buried layers can be directly extracted. The magnetic induction in demagnetized samples can also be probed. These representative characteristics are illustrated by experimental data measured on different systems. In thick AlSiFe films (20 µm), the magnetic induction is determined at the top and bottom interfaces. In thin Co layers (250 nm), the magnetic induction of ferromagnetic domains in the demagnetized state is evaluated.

Refraction of polarized neutrons on boundaries of a magnetic film

Abstract Refraction of polarized neutrons on separate boundaries of magnetic film was investigated. The effects of neutron spin-flip and spatial splitting of a polarized neutron beam were observed. The values of the magnetization vector near the interfaces were determined.

Neutron methods for the direct determination of the magnetic induction in thick films

Abstract We review different neutron methods which allow extracting directly the value of the magnetic induction in thick films: Larmor precession, Zeeman spatial beam-splitting and neutron spin resonance. Resulting parameters obtained by the neutron methods and standard magnetometry technique are presented and compared. The possibilities and specificities of the neutron methods are discussed.

Neutron resonances in planar waveguides

We report on the results of the experimental investigation of the spectral width of neutron resonances in planar waveguides using the time-of-flight method and recording the microbeam emerging from the waveguide end. Experimental data are compared with the results of theoretical calculations.

Channeling of Neutrons in a Planar Waveguide

The propagation of neutrons in the middle layer of a planar waveguide in the form of a three-layer thin film has been investigated. The microbeam from the end face of the film has been registered. The neutron channeling length has been measured as a function of the thickness of the upper waveguide layer and the resonance order. The experimental data have been compared with theoretical results.

Reflection of neutrons from a magnetic film placed in static and oscillating magnetic fields

Measurements of polarized-neutron reflection from magnetic films placed in a static magnetic field and in an oscillating magnetic field perpendicular to it are described. The process of diffuse neutron scattering involving energy transfer from a RF electromagnetic field to neutrons has been studied. Neutron magnetic resonance has been detected, and splitting of the polarized beam of neutrons reflected from a film has been discovered.