Neutron spin echo study of low-Tc ferrofluid

V. T. Lebedev, G. P. Gordeev, A. I. Sibilev, V. V. Klyubin, G. Török, L. Cser, Gy Kali, L. Varga

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

We studied the diffusion of single domain particles of Mn0.3Zn0.7(Fe2O4) (Rp ≈ 100 Å) stabilized by oleic acid in dodecane near the transition temperature Tc of particles from superparamagnetic to paramagnetic state. The structure of the ferrofluid has been studied by small angle neutron scattering. We found a strong density fluctuation near Tc ≈ 20°C and H = 0, induced by critical spin diffusion. In addition, we studied this system using neutron spin echo (NSE) inelastic scattering. The temperature variation of the self-correlation function Gs(T, q, t) = exp[ - q2D (t/τ/β(T)] at momentum transfer q = 0.07 Å-1 in the time interval t = 0.5-40 ns reveals strong influence of magnetic fluctuations on the mobility: these fluctuations decrease the diffusion rate D and induce stretched relaxation (β ≈ 0.6) at T <Tc ≈ 16°C. Above Tc, Stokes diffusion dominates (β ≈ 1)

Original languageEnglish
Pages (from-to)80-83
Number of pages4
JournalJournal of Magnetism and Magnetic Materials
Volume201
Issue number1-3
Publication statusPublished - Jul 1999

Fingerprint

Magnetic fluids
ferrofluids
echoes
Neutrons
neutrons
Inelastic scattering
oleic acid
Momentum transfer
Oleic acid
Oleic Acid
Neutron scattering
Superconducting transition temperature
momentum transfer
inelastic scattering
neutron scattering
transition temperature
intervals
Temperature
temperature

Keywords

  • Magnetic ordering
  • Magnetic transition
  • Neutron inelastic scattering

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Lebedev, V. T., Gordeev, G. P., Sibilev, A. I., Klyubin, V. V., Török, G., Cser, L., ... Varga, L. (1999). Neutron spin echo study of low-Tc ferrofluid. Journal of Magnetism and Magnetic Materials, 201(1-3), 80-83.

Neutron spin echo study of low-Tc ferrofluid. / Lebedev, V. T.; Gordeev, G. P.; Sibilev, A. I.; Klyubin, V. V.; Török, G.; Cser, L.; Kali, Gy; Varga, L.

In: Journal of Magnetism and Magnetic Materials, Vol. 201, No. 1-3, 07.1999, p. 80-83.

Research output: Contribution to journalArticle

Lebedev, VT, Gordeev, GP, Sibilev, AI, Klyubin, VV, Török, G, Cser, L, Kali, G & Varga, L 1999, 'Neutron spin echo study of low-Tc ferrofluid', Journal of Magnetism and Magnetic Materials, vol. 201, no. 1-3, pp. 80-83.
Lebedev VT, Gordeev GP, Sibilev AI, Klyubin VV, Török G, Cser L et al. Neutron spin echo study of low-Tc ferrofluid. Journal of Magnetism and Magnetic Materials. 1999 Jul;201(1-3):80-83.
Lebedev, V. T. ; Gordeev, G. P. ; Sibilev, A. I. ; Klyubin, V. V. ; Török, G. ; Cser, L. ; Kali, Gy ; Varga, L. / Neutron spin echo study of low-Tc ferrofluid. In: Journal of Magnetism and Magnetic Materials. 1999 ; Vol. 201, No. 1-3. pp. 80-83.
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AU - Cser, L.

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