scholarly journals Feasibility of Probing the Filler Restructuring in Magnetoactive Elastomers by Ultra-Small-Angle Neutron Scattering

2021 ◽  
Vol 11 (10) ◽  
pp. 4470
Author(s):  
Inna A. Belyaeva ◽  
Jürgen Klepp ◽  
Hartmut Lemmel ◽  
Mikhail Shamonin
Keyword(s):  
Magnetic Field ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Iron Particles ◽  
Filler Particles ◽  
The Magnetic Field ◽  
Magnetoactive Elastomer

Ultra-small-angle neutron scattering (USANS) experiments are reported on isotropic magnetoactive elastomer (MAE) samples with different concentrations of micrometer-sized iron particles in the presence of an in-plane magnetic field up to 350 mT. The effect of the magnetic field on the scattering curves is observed in the scattering vector range between 2.5 × 10−5 and 1.85 × 10−4 Å−1. It is found that the neutron scattering depends on the magnetization history (hysteresis). The relation of the observed changes to the magnetic-field-induced restructuring of the filler particles is discussed. The perspectives of employing USANS for investigations of the internal microstructure and its changes in magnetic field are considered.

Application of small-angle neutron scattering to the study of forces between magnetically chained monodisperse ferrofluid emulsion droplets

2013 ◽  
Vol 47 (1) ◽  
pp. 41-52 ◽  
Author(s):  
N. Jain ◽  
C. K. Liu ◽  
B. S. Hawkett ◽  
G. G. Warr ◽  
W. A. Hamilton
Keyword(s):  
Magnetic Field ◽  
Neutron Scattering ◽  
Droplet Size ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Colloidal Particles ◽  
Optical Measurements ◽  
Magnetic Field Direction ◽  
Emulsion Droplets ◽  
The Magnetic Field

The optical magnetic chaining technique (MCT) developed by Leal-Calderon, Stora, Mondain-Monval, Poulin & Bibette [Phys. Rev. Lett.(1994),72, 2959–2962] allows precise measurements of force profiles between droplets in monodisperse ferrofluid emulsions. However, the method lacks anin situdetermination of droplet size and, therefore, requires a combination of separately acquired measurements of droplet chain periodicityversusan applied magnetic field from optical Bragg scattering and droplet diameter inferred from dynamic light scattering (DLS) to recover surface force–distance profiles between the colloidal particles. Compound refractive lens (CRL) focused small-angle neutron scattering (SANS) MCT should result in more consistent measurements of droplet size (form factor measurements in the absence of field) and droplet chaining period (from structure factor peaks when the magnetic field is applied), and, with access to shorter length scales, extend force measurements to closer approaches than possible by optical measurements. This article reports on CRL-SANS measurements of monodisperse ferrofluid emulsion droplets aligned in straight chains by an applied field perpendicular to the incident beam direction. Analysis of the scattering from the closely spaced droplets required algorithms that carefully treated resolution and its effect on mean scattering vector magnitudes in order to determine droplet size and chain periods to sufficient accuracy. At lower applied fields, scattering patterns indicate structural correlations transverse to the magnetic field direction owing to the formation of intermediate structures in early chain growth.

scholarly journals Magnetic field dependent small-angle neutron scattering on a Co nanorod array: evidence for intraparticle spin misalignment

2014 ◽  
Vol 47 (3) ◽  
pp. 992-998 ◽  
Author(s):  
A. Günther ◽  
J.-P. Bick ◽  
P. Szary ◽  
D. Honecker ◽  
C. D. Dewhurst ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Neutron Scattering ◽  
Cross Section ◽  
Field Dependence ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Strong Field ◽  
Structural Parameters ◽  
Nanorod Array ◽  
Field Dependent

The structural and magnetic properties of a cobalt nanorod array have been studied by means of magnetic field dependent small-angle neutron scattering (SANS). Measurement of the unpolarized SANS cross section dΣ/dΩ of the saturated sample in the two scattering geometries where the applied magnetic fieldHis either perpendicular or parallel to the wavevectorkiof the incoming neutron beam allows one to separate nuclear from magnetic SANS, without employing the usual sector-averaging procedure. The analysis of the SANS data in the saturated state provides structural parameters (rod radius and centre-to-centre distance) that are in good agreement with results from electron microscopy. Between saturation and the coercive field, a strong field dependence of dΣ/dΩ is observed (in both geometries), which cannot be explained using the conventional expression of the magnetic SANS cross section of magnetic nanoparticles in a homogeneous nonmagnetic matrix. The origin of the strong field dependence of dΣ/dΩ is believed to be related to intradomain spin misalignment, due to magnetocrystalline and magnetoelastic anisotropies and magnetostatic stray fields.

scholarly journals Aligning self-assembled perylene bisimides in a magnetic field

2018 ◽  
Vol 54 (78) ◽  
pp. 10977-10980 ◽  
Author(s):  
Emily R. Draper ◽  
Matthew Wallace ◽  
Dirk Honecker ◽  
Dave J. Adams
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Electrochemical Techniques ◽  
Perylene Bisimide ◽  
Self Assembled ◽  
Perylene Bisimides

Directional dependent photoresponsive perylene bisimide thin films can be made by aligning and drying under a magnetic field. This can be monitored by NMR and small angle neutron scattering and assessed by imaging and electrochemical techniques.

scholarly journals First Experiment of Spin Contrast Variation Small-Angle Neutron Scattering on the iMATERIA Instrument at J-PARC

2020 ◽  
Vol 4 (4) ◽  
pp. 33 ◽  
Author(s):  
Yohei Noda ◽  
Tomoki Maeda ◽  
Takayuki Oku ◽  
Satoshi Koizumi ◽  
Tomomi Masui ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Coherent Scattering ◽  
Proton Spin ◽  
Neutron Polarization ◽  
Stray Magnetic Field ◽  
Beam Experiment ◽  
Neutron Wavelength

Recently, we have developed a novel dynamic nuclear polarization (DNP) apparatus with a magnetic field of 7 T and a sample temperature of 1 K. High proton spin polarizations from −84% to 76%, for TEMPO doped polystyrene samples, have been demonstrated. This DNP apparatus satisfies the simultaneous requirement for quick and easy sample exchange and high DNP performance. On the iMATERIA (BL20) instrument at J-PARC, the first beam experiment using this DNP apparatus has been performed. For this experiment, the beamline was equipped with a supermirror polarizer. The stray magnetic field due to the superconducting magnet for DNP was also evaluated. The stray magnetic field plays an important role for in maintaining the neutron polarization during the transportation from the polarizer to the sample. The small-angle neutron scattering (SANS) profiles of silica-filled rubber under dynamically polarized conditions are presented. By applying our new analytical approach for SANS coherent scattering intensity, neutron polarization (PN) as a function of neutron wavelength was determined. Consequently, for the neutron wavelength, range from 4 Å to 10 Å, |PN| was sufficient for DNP-SANS studies.

scholarly journals Simulations of foil-based spin-echo (modulated) small-angle neutron scattering with a sample using McStas

2021 ◽  
Vol 54 (1) ◽  
pp. 195-202
Author(s):  
Wim G. Bouwman ◽  
Erik B. Knudsen ◽  
Linda Udby ◽  
Peter Willendrup
Keyword(s):  
Magnetic Field ◽  
Elastic Scattering ◽  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Spin Echo ◽  
Transmitted Beam ◽  
Further Development ◽  
Theory And Experiments ◽  
Good Agreement

For the further development of spin-echo techniques to label elastic scattering it is necessary to perform simulations of the Larmor precession of neutron spins in a magnetic field. The details of some of these techniques as implemented at the reactor in Delft are simulated. First, the workings of the magnetized foil flipper are simulated. A full virtual spin-echo small-angle neutron scattering instrument is built and tested without and with a realistic scattering sample. It is essential for these simulations to have a simulated sample that also describes the transmitted beam of unscattered neutrons, which usually is not implemented for the simulation of conventional small-angle neutron scattering (SANS) instruments. Finally, the workings of a spin-echo modulated small-angle neutron scattering (SEMSANS) instrument are simulated. The simulations are in good agreement with theory and experiments. This setup can be extended to include realistic magnetic field distributions to fully predict the features of future Larmor labelling elastic-scattering instruments. Configurations can now be simulated for more complicated combinations of SANS with SEMSANS.

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