Characterization of the Grain Size in Ferromagnetic Colloids: Comparing Torsional-Pendulum Measurements with Standard Complementary Methods

Embs, Jan Peter; Müller, H. W.; Krill, Carl E.; Meyer, F.; Natter, Harald; Müller, Bettina; Wiegand, Simone; Lücke, M.; Knorr, K.; Hempelmann, Rolf

doi:10.1524/zpch.2006.220.2.153

Cited by 13 publications

(11 citation statements)

References 19 publications

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“…N°F 083094CX from Ferrotec, Co.͒ which contains magnetite particles stabilized in synthetic hydrocarbon by a surfactant. The data were fitted according to Embs et al 15 by The same is true for the critical induction of the Rosensweig instability in the ferrofluid, affected sensitively by these parameters.…”

Section: A Materialsmentioning

confidence: 99%

Viscoelasticity of mono- and polydisperse inverse ferrofluids

Saldivar-Guerrero

Richter

Rehberg

et al. 2006

The Journal of Chemical Physics

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We report on measurements of a magnetorheological model fluid created by dispersing nonmagnetic microparticles of polystyrene in a commercial ferrofluid. The linear viscoelastic properties as a function of magnetic field strength, particle size, and particle size distribution are studied by oscillatory measurements. We compare the results with a magnetostatic theory proposed by De Gans et al. [Phys. Rev. E 60, 4518 (1999)] for the case of gap spanning chains of particles. We observe these chain structures via a long distance microscope. For monodisperse particles we find good agreement of the measured storage modulus with theory, even for an extended range, where the linear magnetization law is no longer strictly valid. Moreover we compare for the first time results for mono- and polydisperse particles. For the latter, we observe an enhanced storage modulus in the linear regime of the magnetization.

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Section: A Materialsmentioning

confidence: 99%

Viscoelasticity of mono- and polydisperse inverse ferrofluids

Saldivar-Guerrero

Richter

Rehberg

et al. 2006

The Journal of Chemical Physics

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“…[308] Other techniques include magneto-granulometry, photon correlation spectroscopy, Raman spectroscopy, and torsional pendulum measurements. [216,309] Vibrational spectroscopy is also a powerful tool for studying the fundamental properties of magnetic oxides. The finite scale length effect for CoFe 2 O 4 inverse spinel MNPs was studied from infrared vibrational properties by observing the strong magnetoelastic coupling.…”

Section: Characterization Techniquesmentioning

confidence: 99%

Ferrofluids: Synthetic Strategies, Stabilization, Physicochemical Features, Characterization, and Applications

Joseph

Mathew

2014

ChemPlusChem

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Ferrofluids (FFs) or magnetic nanofluids are incredible smart materials consisting of ultrafine magnetic nanoparticles suspended in a liquid carrier medium, which exhibit both fluidity and magnetic controllability. Studies involving the dynamics and physicochemical properties of these magnetic nanofluids are an interdisciplinary area of research attracting researchers from different fields of science and technology. Herein, a comprehensive Review on the different aspects of FF research is presented. First, the synthesis and stabilization of various types of FFs are discussed followed by their physicochemical features such as polydispersity, magnetic behavior, dipolar interactions, formation of chainlike aggregates, and long‐range ordering. The Review also details the rheological and thermal properties, dynamic instabilities, phase behavior, and particle assemblies in FFs to form complex multipolar geometries, photonic nanostructures, labyrinth structures, thin films, and droplets. Many important characterization techniques for probing FF properties are also briefly discussed, and the numerous innovative applications and future prospects of FFs are outlined.

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“…For our calculations we use typical values of the parameters [25][26][27][28] that characterize the ferrofluid APG933 of FerroTec: M sat mat 450 kA/m, = 4.1%, ρν = 0.5 Pa s, s = 2 nm, f 0 = 10 9 Hz, and K = 15 kJ/m 3 . The equilibrium magnetization M eq (H ) of APG933 is obtained with a polydisperse fit to experimental data that is described in detail in Ref.…”

Section: A Ferrofluid Parametersmentioning

confidence: 99%

Elongational flow effects on the vortex growth out of Couette flow in ferrofluids

et al. 2013

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The growth behavior of stationary axisymmetric vortices and of oscillatory, nonaxisymmetric spiral vortices in Taylor-Couette flow of a ferrofluid in between differentially rotating cylinders is analyzed using a numerical linear stability analysis. The investigation is done as a function of the inner and outer cylinder's rotation rates, the axial wave number of the vortex flows, and the magnitude of an applied homogeneous axial magnetic field. In particular, the consequences of incorporating elongational flow effects in the magnetization balance equation on the marginal control parameters that separate growth from decay behavior are determined. That is done for several values of the transport coefficient that measures the strength of these effects.

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Characterization of the Grain Size in Ferromagnetic Colloids: Comparing Torsional-Pendulum Measurements with Standard Complementary Methods

Cited by 13 publications

References 19 publications

Viscoelasticity of mono- and polydisperse inverse ferrofluids

Viscoelasticity of mono- and polydisperse inverse ferrofluids

Ferrofluids: Synthetic Strategies, Stabilization, Physicochemical Features, Characterization, and Applications

Elongational flow effects on the vortex growth out of Couette flow in ferrofluids

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