0000000000201689

AUTHOR

Guillaume Mériguet

showing 3 related works from this author

The cage elasticity and under-field structure of concentrated magnetic colloids probed by small angle X-ray scattering

2013

International audience; In the present study we probe the bulk modulus and the structure of concentrated magnetic fluids by small angle X-ray scattering. The electrostatically stabilized nanoparticles experience a repulsive interparticle potential modulated by dipolar magnetic interactions. On the interparticle distance length scale, we show that nanoparticles are trapped under-field in oblate cages formed by their first neighbours. We propose a theoretical model of magnetostriction for the field-induced deformation of the cage. This model captures the anisotropic features of the experimentally observed scattering pattern on the local scale in these strongly interacting colloidal dispersions

Length scaleCondensed Matter::Quantum GasesBulk modulusMaterials scienceCondensed matter physicsScatteringSmall-angle X-ray scatteringMagnetostriction02 engineering and technologyGeneral ChemistryElasticity (physics)021001 nanoscience & nanotechnologyCondensed Matter Physics01 natural sciencesCondensed Matter::Soft Condensed MatterDipoleCrystallography0103 physical sciences010306 general physics0210 nano-technologyAnisotropy[PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
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Relaxation of the field-induced structural anisotropy in a rotating magnetic fluid

2009

The relaxation of field-induced anisotropy in a magnetic fluid with dominant repulsion is theoretically modeled and experimentally measured by small angle neutron scattering on a sample rotating at angular velocity ω. The scattered pattern distortion scales as the Mason number Mn=ω·τq, τq being the q-dependent diffusion time of nanoparticles. The model accounts for the magnetophoretical drift in the non-homogeneous self-magnetic field of the assembly, continuously created by the thermal noise. The Mn-dependence of the pattern distortion is well described without any adjustable parameter.

PhysicsCondensed matter physicsField (physics)business.industryRelaxation (NMR)General Physics and AstronomyNanoparticleAngular velocitySmall-angle neutron scatteringOpticsDistortionDiffusion (business)businessAnisotropyEPL (Europhysics Letters)
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Thermodiffusion anisotropy under a magnetic field in ionic liquid-based ferrofluids

2021

International audience; Ferrofluids based on maghemite nanoparticles (NPs), typically 10 nm in diameter, are dispersed in an ionic liquid (1-ethyl 3-methylimidazolium bistriflimide - EMIM-TFSI). The average interparticle interaction is found to be repulsive by small angle scattering of X-rays and of neutrons, with a second virial coefficient A2 = 7.3. A moderately concentrated sample at Φ = 5.95 vol% is probed by forced Rayleigh scattering under an applied magnetic field (up to H = 100 kA m-1) from room temperature up to T = 460 K. Irrespective of the values of H and T, the NPs in this study are always found to migrate towards the cold region. The in-field anisotropy of the mass diffusion c…

[PHYS]Physics [physics]FerrofluidMaterials scienceCondensed matter physics02 engineering and technologyGeneral Chemistry010402 general chemistry021001 nanoscience & nanotechnologyCondensed Matter Physics01 natural sciences0104 chemical sciencesMagnetic fieldchemistry.chemical_compoundDipolechemistryVirial coefficientIonic liquidBistriflimideSmall-angle scattering0210 nano-technologyAnisotropySoft Matter
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