Retrieval of depth profile of nano scale thin films by one directional polarization analysis in neutron specular reflectometry

TL;DR

This paper proposes a practical neutron reflectometry method to determine the depth profile of nano-scale thin films using polarization analysis in the same direction as the incident beam, suitable for current reflectometers.

Contribution

A new polarization analysis technique using two magnetic field orientations enables phase determination with existing reflectometers.

Findings

Method successfully determines phase of reflection coefficient.

Compatible with current neutron reflectometry instruments.

Addresses practical limitations of previous polarization-based methods.

Abstract

Recently it has been shown that the modules and phase of complex reflection coefficient can be determined by using a magnetic substrate and polarized neutrons. Several other methods have also been worked out based on measurement of polarizations of reflected neutrons from magnetic reference layers and magnetic substrate. However, due to the fact that available reflectometers are limited in the choice of polarization of reflected beam in the same direction as the polarization of the incident beam, neither of the methods which are based on polarization analysis, has been proven to be experimentally practical. In this paper, we have proposed a new method for determining the phase of reflection coefficient which is based on two measurements of polarization which correspond to two magnetic fields with the same magnitudes and different orientations. The polarization analysis is performed in the same direction as the polarization of the incident beam and is well suited for available reflectometers. The problems envisaged in implementation of the method are also discussed.