Premium
Development of spin‐contrast‐variation neutron reflectometry for the structural analysis of multilayer films
Author(s) -
Kumada Takayuki,
Akutsu Kazuhiro,
Ohishi Kazuki,
Morikawa Toshiaki,
Kawamura Yukihiko,
Sahara Masae,
Suzuki Jun-ichi,
Torikai Naoya
Publication year - 2019
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576719010616
Subject(s) - neutron reflectometry , neutron , reflectometry , materials science , polystyrene , x ray reflectivity , optics , reflectivity , monolayer , molecular physics , polarization (electrochemistry) , neutron scattering , ellipsometry , scattering , small angle neutron scattering , thin film , chemistry , physics , polymer , nuclear physics , nanotechnology , composite material , time domain , computer science , computer vision
The spin‐contrast‐variation neutron reflectometry technique was developed for the structural analysis of multilayer films. Polarized‐neutron reflectivity curves of film samples vary as a function of their proton polarization ( P H ). The P H ‐dependent reflectivity curves of a polystyrene monolayer film were precisely reproduced using a common set of structural parameters and the P H ‐dependent neutron scattering length density of polystyrene. This result ensures that these curves are not deformed by inhomogeneous P H but can be used for structural analysis. Unpolarized reflectivity curves of poly(styrene‐ block ‐isoprene) films were reproduced using a flat free‐surface model but P H ‐dependent polarized reflectivity curves were not. The global fit of the P H ‐dependent multiple reflectivity curves revealed that holes with a depth corresponding to one period of the periodic lamellae of microphase‐separated polystyrene and polyisoprene domains were produced on the surface of the films, which agrees with the microscopic results. In this manner, the spin‐contrast‐variation neutron reflectometry technique determines the structure of multiple surfaces and interfaces in a film sample while excluding the incorrect structure that accidentally accounts for a single unpolarized reflectivity curve only.