Morphological and crystallographic orientation of hematite spindles in an applied magnetic field

Zákutná, Dominika; Falke, Yannic; Dresen, Dominique; Prévost, Sylvain; Bender, Philipp; Honecker, Dirk; Disch, Sabrina

doi:10.1039/c8nr09583c

Cited by 22 publications

(30 citation statements)

References 47 publications

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“…This work showed that the magnetic and orientation order parameters of magnetic single-domain nanospindles can be described by an oriented ellipsoid with the easy axis of magnetization lying in the equatorial plane of the particle. Texture analysis of the WAXS data further confirmed that the magnetic easy axis is located in the basal plane of the hematite crystal lattice [55]. The field-induced orientation of hematite particles can be used to probe the viscoelastic response of a gel such as that formed by poly(N-isopropylacrylamide) (PNIPAM) and correlate with the microrheological parameters [53].…”

Section: Equilibrium Nanostructure and Interactionsmentioning

confidence: 78%

“…A field-induced isotropic to nematic transition can be observed in these suspensions. Orientation ordering of spindle-shaped hematite particles in a magnetic field was studied by combined SAXS and WAXS [55]. This work showed that the magnetic and orientation order parameters of magnetic single-domain nanospindles can be described by an oriented ellipsoid with the easy axis of magnetization lying in the equatorial plane of the particle.…”

Section: Equilibrium Nanostructure and Interactionsmentioning

confidence: 99%

“…The phase behavior of anisotropic colloids is very sensitive to applied fields such as electric or magnetic fields [53][54][55]. A field-induced isotropic to nematic transition can be observed in these suspensions.…”

Section: Equilibrium Nanostructure and Interactionsmentioning

confidence: 99%

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Synchrotron Scattering Methods for Nanomaterials and Soft Matter Research

Narayanan

Konovalov

2020

Materials

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This article aims to provide an overview of broad range of applications of synchrotron scattering methods in the investigation of nanoscale materials. These scattering techniques allow the elucidation of the structure and dynamics of nanomaterials from sub-nm to micron size scales and down to sub-millisecond time ranges both in bulk and at interfaces. A major advantage of scattering methods is that they provide the ensemble averaged information under in situ and operando conditions. As a result, they are complementary to various imaging techniques which reveal more local information. Scattering methods are particularly suitable for probing buried structures that are difficult to image. Although, many qualitative features can be directly extracted from scattering data, derivation of detailed structural and dynamical information requires quantitative modeling. The fourth-generation synchrotron sources open new possibilities for investigating these complex systems by exploiting the enhanced brightness and coherence properties of X-rays.

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Section: Equilibrium Nanostructure and Interactionsmentioning

confidence: 78%

Section: Equilibrium Nanostructure and Interactionsmentioning

confidence: 99%

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Synchrotron Scattering Methods for Nanomaterials and Soft Matter Research

Narayanan

Konovalov

2020

Materials

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“…Moreover, in many studies structural form-factor models, adapted from nuclear SANS, are utilized, which fail to account for the existing spin inhomogeneity inside magnetic nanostructured systems. Only recently the analysis of the total (magnetic and/or nuclear) 2D patterns was introduced, either by directly calculating the cross section in reciprocal space [25,26] or by determining the real-space 2D correlation functions. [27,28] In this study, we introduce a new method to extract the underlying 2D correlation functions from 2D magnetic SANS patterns.…”

Section: Introductionmentioning

confidence: 99%

Unraveling Nanostructured Spin Textures in Bulk Magnets

et al. 2020

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One of the key challenges in magnetism remains the determination of the nanoscopic magnetization profile within the volume of thick samples, such as permanent ferromagnets. Thanks to the large penetration depth of neutrons, magnetic small‐angle neutron scattering (SANS) is a powerful technique to characterize bulk samples. The major challenge regarding magnetic SANS is accessing the real‐space magnetization vector field from the reciprocal scattering data. In this study, a fast iterative algorithm is introduced that allows one to extract the underlying 2D magnetic correlation functions from the scattering patterns. This approach is used here to analyze the magnetic microstructure of Nanoperm, a nanocrystalline alloy which is widely used in power electronics due to its extraordinary soft magnetic properties. It can be shown that the computed correlation functions clearly reflect the projection of the 3D magnetization vector field onto the detector plane, which demonstrates that the used methodology can be applied to probe directly spin textures within bulk samples with nanometer resolution.

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“…When a magnetic field is applied, anisometric magnetic nanoparticles align with their magnetic easy axis along the field [29][30][31][32][33][34][35][36]. If the long nanoparticle axis aligns perpendicular to the flow direction, the aligned nanoparticles oppose resistance to the flow resulting in an increase fluid viscosity.…”

Section: Introductionmentioning

confidence: 99%

In situ magnetorheological SANS setup at Institut Laue-Langevin

et al. 2020

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A magnetorheological sample environment is presented that allows for in situ magnetic field and shear flow during small-angle neutron scattering (SANS) measurements and is now available at the Institut Laue-Langevin (ILL). The setup allows performing simultaneous magnetorheological measurements together with the investigation of structural and magnetic changes on the nanometer length scale underlying the rheological response of ferrofluids. We describe the setup consisting of a commercial rheometer and a custom-made set of Helmholtz coils and show exemplarily data on the field and shear flow alignment of a dispersion of hematite nanospindles in water.

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Morphological and crystallographic orientation of hematite spindles in an applied magnetic field

Abstract: The magnetic response of spindle-shaped hematite (α-Fe2O3) nanoparticles was investigated by simultaneous small-angle and wide-angle X-ray scattering (SAXS/WAXS) experiments.

Cited by 22 publications

References 47 publications

Synchrotron Scattering Methods for Nanomaterials and Soft Matter Research

Synchrotron Scattering Methods for Nanomaterials and Soft Matter Research

Unraveling Nanostructured Spin Textures in Bulk Magnets

In situ magnetorheological SANS setup at Institut Laue-Langevin

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