The initial magnetic susceptibility of polydisperse ferrofluids: A comparison between experiment and theory over a wide range of concentration
Autor: | Anna Yu. Solovyova, Ekaterina A. Elfimova, Olga A. Goldina, Aleksandr V. Lebedev, Alexey O. Ivanov |
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Rok vydání: | 2016 |
Předmět: |
Range (particle radiation)
Ferrofluid Materials science Condensed matter physics General Physics and Astronomy 01 natural sciences Magnetic susceptibility Virial theorem 010305 fluids & plasmas chemistry.chemical_compound Virial coefficient chemistry 0103 physical sciences Magnetic nanoparticles Physical and Theoretical Chemistry 010306 general physics Magnetite Cluster expansion |
Zdroj: | The Journal of Chemical Physics. 145:084909 |
ISSN: | 1089-7690 0021-9606 |
Popis: | Temperature dependencies of the static initial magnetic susceptibility for ferrofluids at various concentrations are studied using experiment and statistical-mechanical theories. Magnetic susceptibility measurements are carried out for twelve samples of magnetite-based fluids stabilized with oleic acid over a wide range of temperatures (210 K ≲T ≲ 390 K); all samples have the same granulometric composition but different volume ferroparticle concentrations (0.2 ≲ φ ≲ 0.5). Experimental results are analyzed using three theories: the second-order modified mean-field theory (MMF2) [A. O. Ivanov and O. B. Kuznetsova, Phys. Rev. E 64, 41405 (2001)]; its correction for polydisperse ferrofluids arising from Mayer-type cluster expansion and taking into account the first terms of the polydisperse second virial coefficient [A. O. Ivanov and E. A. Elfimova, J. Magn. Magn. Mater 374, 327 (2015)]; and a new theory based on MMF2 combined with the first terms of the polydisperse second and third virial contributions to susceptibility. It turns out that the applicability of each theory depends on the experimental sample density. If twelve ferrofluid samples are split into three groups of strong, moderate, and low concentrated fluids, the temperature dependences of the initial magnetic susceptibility in each group are very precisely described by one of the three theories mentioned above. The determination of a universal formula predicting a ferrofluid susceptibility over a broad range of concentrations and temperatures remains as a challenge. |
Databáze: | OpenAIRE |
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