Techniques de diffusion des neutrons en incidence rasante pour les nanosciences

Grazing incidence small-angle neutron scattering (GISANS) provides access to interfacial properties, e.g., in soft matter on polymers adsorbed at a solid substrate. Simulations in the frame of the distorted wave Born approximation using the BornAgain software allow to understand and quantify the scattering pattern above and below the sample horizon, in reflection and transmission, respectively. The small-angle scattering from the interfacial layer, visible around the transmitted beam, which might contribute also on the side of the reflected beam, can be understood in this way and be included into the analysis. Background reduction by optimized sample cell design is supported by simulations, paving the way for an optimized GISANS cell.

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“…At α f = α i specular reflection occurs. The interesting part however for GISANS is the off-specular or diffuse scattering, where α f = α i [31].…”

Section: Principles Of Grazing Incidence Scatteringmentioning

confidence: 99%

Grazing Incidence Small-Angle Neutron Scattering: Background Determination and Optimization for Soft Matter Samples

et al. 2021

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“…24,25 By combining a magnetic layer of known structure into an otherwise unknown film structure, one can extract the phase information with polarized neutron reflectometry, [24][25][26] thus enabling the direct solution to the one-dimensional, real space structure of the adsorbed thin film. [27][28][29][30][31] A novel prototype Halbach ring magnet has been designed for the magnetism reflectometer [32][33][34] at the Spallation Neutron Source (SNS) located at Oak Ridge National Laboratory (ORNL), using the Big Area Additive Manufacturing (BAAM) printer located at ORNL's Material Demonstration Facility. Polyphenylene sulfide (PPS) is reported to be more resistant to c-rays 35 and electron-beam exposure than most other polymers.…”

Section: Introductionmentioning

confidence: 99%

Additively Manufactured NdFeB Polyphenylene Sulfide Halbach Magnets to Generate Variable Magnetic Fields for Neutron Reflectometry

Lamichhane¹,

Charlton²,

Andrews³

et al. 2022

3D Printing and Additive Manufacturing

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Halbach arrays are the most efficient closed structures for generating directed magnetic fields and gradients, and are widely used in various electric machines. We utilized fused deposition modeling-based Big Area Additive Manufacturing technology to print customized, compensated concentric Halbach array rings, using polyphenylene sulfide-bonded NdFeB permanent magnets for polarized neutron reflectometry. The Halbach rings could generate a 0 £ B £ 0.30 T field, while preserving 90% polarization of an axial neutron beam. Polarized neutron beams are used to study a wide range of structural and magnetic phenomena spanning physics, chemistry, and biology. In this study, we demonstrate the effectiveness of additive manufacturing for producing prototype Halbach arrays, characterize their magnetic properties, and generated magnetic fields, and discuss the conservation of neutron beam polarization as a function of magnetic field.

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La_0.6Sr_0.4CoO_3−δ Films Under Deoxygenation: Magnetic And Electronic Transitions Are Apart from The Structural Phase Transition

He,

Petracic,

Lauter

et al. 2024

Adv Funct Materials

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Topotactic phase transitions induced by changes in the oxygen vacancy concentration can largely alter the physical properties of complex oxides, including electronic and magnetic phases, while maintaining the structural integrity of the crystal lattice. An oxygen‐vacancy‐induced topotactic phase transition from perovskite (PV) to brownmillerite (BM) is achieved in epitaxial La0.6Sr0.4CoO3−δ (LSCO) thin films. Two novel intermediate states with different oxygen content are identified by X‐ray diffraction, which involves a single‐phase reduced PV state and a mixed state of co‐existing PV and BM. The combination of depth‐sensitive polarized neutron reflectometry (PNR) and Rutherford backscattering (RBS) allows a quantitative determination of magnetization and the mean oxygen content in all states, revealing a continuous transition from La0.6Sr0.4CoO2.97 to La0.6Sr0.4CoO2.5. BM formation is observed for an LSCO layer with an oxygen content of 2.67, while the magnetic and electronic transition already occurs for a layer with a higher oxygen content of 2.77 (and above) and in the absence of a BM signature. These results demonstrate that the physics of electronic metal‐to‐insulator transition (MIT), magnetic ferromagnet‐to‐non‐ferromagnet transition (FM‐to‐non‐FM), and structural PV‐to‐BM phase transition should be considered within the framework of separate but interrelated processes.

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Techniques de diffusion des neutrons en incidence rasante pour les nanosciences

Abstract: Article published by EDP Sciences and available at

Cited by 23 publications

References 29 publications

Grazing Incidence Small-Angle Neutron Scattering: Background Determination and Optimization for Soft Matter Samples

Grazing Incidence Small-Angle Neutron Scattering: Background Determination and Optimization for Soft Matter Samples

Additively Manufactured NdFeB Polyphenylene Sulfide Halbach Magnets to Generate Variable Magnetic Fields for Neutron Reflectometry

La_0.6Sr_0.4CoO_3−δ Films Under Deoxygenation: Magnetic And Electronic Transitions Are Apart from The Structural Phase Transition

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Techniques de diffusion des neutrons en incidence rasante pour les nanosciences

Abstract: Article published by EDP Sciences and available at

Cited by 23 publications

References 29 publications

Grazing Incidence Small-Angle Neutron Scattering: Background Determination and Optimization for Soft Matter Samples

Grazing Incidence Small-Angle Neutron Scattering: Background Determination and Optimization for Soft Matter Samples

Additively Manufactured NdFeB Polyphenylene Sulfide Halbach Magnets to Generate Variable Magnetic Fields for Neutron Reflectometry

La0.6Sr0.4CoO3−δ Films Under Deoxygenation: Magnetic And Electronic Transitions Are Apart from The Structural Phase Transition

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Product

Resources

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La_0.6Sr_0.4CoO_3−δ Films Under Deoxygenation: Magnetic And Electronic Transitions Are Apart from The Structural Phase Transition