REAL

Roughness replication in neutron supermirrors and periodic multilayers

Veres, Tamás and Cser, László and Bálint, Szabolcs and Sajti, Szilárd (2016) Roughness replication in neutron supermirrors and periodic multilayers. JOURNAL OF APPLIED CRYSTALLOGRAPHY. pp. 1-17. ISSN 0021-8898 (Submitted)

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Abstract

Interface roughness strongly influences the reflectivity of neutron supermirrors (SM) the major components of neutron optical devices. The in-plane and out-of-plane correlation of the interface roughness was studied using neutron and X-ray off-specular reflectometry in DC-sputtered Ni-Ti SMs and periodic multilayers. Roughness correlation is manifested in diffuse scatter plateaus and peaks which are interpreted in terms of Resonant Diffuse Scattering (RDS). A lower estimate of a few 1000 Å out-of-plane correlation length was found by off-set X-ray diffuse scans for periodic Ni-Ti multilayers of various bilayer thicknesses. Detector scans were carried out to observe off-specular neutron scattering from normal and reverse layer sequence SMs. The first order RDS is absent in normal but present in reverse sequence SMs, which is qualitatively explained by kinematical considerations. Distorted Wave Born Approximation simulations of off-specular scattering pattern both of normal and reverse SMs quantitatively reproduces the characteristic features of the measured curves with reasonable parameters, i.e. in-plane and out-of-plane correlation lengths and Hurst parameter of 1200 Å, 4000 Å, 7 Å and 0.5, respectively. The out-of-plane correlation length estimations deduced from SM and periodic multilayer reflectivities are in reasonable agreement with each other.

Item Type: Article
Subjects: Q Science / természettudomány > QC Physics / fizika
Depositing User: Dr Szabolcs Balint
Date Deposited: 26 May 2016 07:27
Last Modified: 04 Apr 2023 11:25
URI: http://real.mtak.hu/id/eprint/35374

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