Towards spatially resolved magnetic small-angle scattering studies by polarized and polarization-analyzed neutron dark-field contrast imaging

Jacopo Valsecchi,Christian Grünzweig,Markus Strobl,Kotaro Saito,Seung Wook Lee,Youngju Kim

doi:10.1038/s41598-021-87335-3

Jacopo Valsecchi, Christian Grünzweig + Show 4 more

Open Access

https://doi.org/10.1038/s41598-021-87335-3

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Abstract

In the past decade neutron dark-field contrast imaging has developed from a qualitative tool depicting microstructural inhomogeneities in bulk samples on a macroscopic scale of tens to hundreds of micrometers to a quantitative spatial resolved small-angle scattering instrument. While the direct macroscopic image resolution around tens of micrometers remains untouched microscopic structures have become assessable quantitatively from the nanometer to the micrometer range. Although it was found that magnetic structures provide remarkable contrast we could only recently introduce polarized neutron grating interferometric imaging. Here we present a polarized and polarization analyzed dark-field contrast method for spatially resolved small-angle scattering studies of magnetic microstructures. It is demonstrated how a polarization analyzer added to a polarized neutron grating interferometer does not disturb the interferometric measurements but allows to separate and measure spin-flip and non-spin-flip small-angle scattering and thus also the potential for a distinction of nuclear and different magnetic contributions in the analyzed small-angle scattering.

Highlights

In the past decade neutron dark-field contrast imaging has developed from a qualitative tool depicting microstructural inhomogeneities in bulk samples on a macroscopic scale of tens to hundreds of micrometers to a quantitative spatial resolved small-angle scattering instrument
The first relevant parameter to asses is the impact of the polarization analyzer and the spin flipper for the incident polarization on the visibility of the beam modulation, which can be exploited
It has been demonstrated that polarization analyses can be added to Talbot-Lau grating interferometers for dark-field contrast imaging

Summary

Introduction

In the past decade neutron dark-field contrast imaging has developed from a qualitative tool depicting microstructural inhomogeneities in bulk samples on a macroscopic scale of tens to hundreds of micrometers to a quantitative spatial resolved small-angle scattering instrument. Besides microstructures like pore distributions and precipitation in bulk condensed matter, in particular magnetic structures such as in particular domain walls were found to provide significant c ontrast[7,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26] The latter enabled outstanding studies of magnetic materials and seminal access to 3D domain structures in the bulk of magnetic m aterials[27,28,29,30,31]. It was significantly later, about half a decade ago, that the quantitative characterization of microstructures based on the probed small-angle neutron scattering in dark-field contrast imaging was u nlocked[32]. Modulation does not need to be interferometric, like in the conventionally applied Talbot-Lau (TL), and that modulation methods other than TL interferometers and gratings in general have been demonstrated for quantitative neutron dark-field contrast imaging as well[1,24,32,33,34,37,38,39,40,41,42]

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