Retrieval of the reflection coefficient in neutron specular reflectometry

TL;DR

This paper introduces a method to fully determine the complex reflection coefficient in neutron specular reflectometry by using polarized neutron beams and magnetic reference layers, enabling substrate effects to be eliminated.

Contribution

The paper presents a novel technique that allows complete retrieval of the reflection coefficient for unknown potentials without substrate interference, using polarization measurements and transfer matrix calculations.

Findings

Method successfully determines complex reflection coefficient

Eliminates substrate effects in measurements

Applicable to unknown real potentials

Abstract

A method is proposed which allows a complete determination of the complex reflection coefficient for any free unknown real potential (i.e., in the case where there is no effective absorption). In this method the unknown layer mounted on top of a known magnetic reference layer in touch with a macroscopic substrate. It lets us to determine the complex reflection coefficient without the effect of the substrate. The method exploits the interference of the spin components of a polarized neutron beam in the presence of a magnetic field. It is based on calculating the polarization of the reflected beam using the elements of transfer matrix and requires the measurement of the polarization in two(one) direction and (two) reflectivity of the reflected beam. A schematic example is presented.