The Role of 11B4C Interlayers in Enhancing Fe/Si Multilayer Performance for Polarized Neutron Mirrors

TL;DR

Incorporating 11B4C interlayers into Fe/Si multilayers enhances interface quality, reflectivity, and polarization, significantly improving performance for polarized neutron mirrors, especially in thinner multilayer structures.

Contribution

This study demonstrates that 11B4C interlayers improve interface sharpness and magnetic properties, leading to better neutron optical performance in Fe/Si multilayers.

Findings

Enhanced interface sharpness with 11B4C interlayers.

Increased reflectivity and polarization in multilayers.

Less impact of interlayers in thicker multilayers.

Abstract

This study investigates the effects of incorporating 11B4C interlayers into Fe/Si multilayers, with a focus on interface quality, reflectivity, polarization, and magnetic properties for polarized neutron optics. It is found that the introduction of 1 {\AA} and 2 {\AA} 11B4C interlayers significantly improves the interface sharpness, reducing interface width and preventing excessive Si diffusion into the Fe layers. X-ray reflectivity and polarized neutron reflectivity measurements show enhanced reflectivity and polarization, with a notable increase in polarization for 30 {\AA} period multilayers. The inclusion of interlayers also helps prevent the formation of iron-silicides, improving both the magnetic properties and neutron optical performance. However, the impact of interlayers is less pronounced in thicker-period multilayers (100 {\AA}), primarily due to the ratio between layer and interface widths. These results suggest that 11B4C interlayers offer a promising route for optimizing Fe/Si multilayer performance in polarized neutron mirrors.