Croatica Chemica Acta, Vol. 88 No. 4, 2015.
Original scientific paper
https://doi.org/10.5562/cca2753
Anomalous Particle Size Dependence of Magnetic Relaxation Phenomena in Goethite Nanoparticles
Cathrine Frandsen
orcid.org/0000-0001-5006-924X
; Department of Physics, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
Daniel Esmarch Madsen
; Department of Physics, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
Chris B. Boothroyd
; Ernst Ruska-Centrum und Peter Grünberg Institut, Forschungszentrum Jülich, D-52425 Jülich, Germany
Steen Mørup
; Department of Physics, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark
Abstract
By use of Mössbauer spectroscopy we have studied the magnetic properties of samples of goethite nanoparticles with different particle size. The spectra are influenced by fluctuations of the magnetization directions, but the size dependence is not in accordance with the Néel-Brown expression for superparamagnetic relaxation of the magnetization vectors of the particles as a whole. The data suggest that the magnetic fluctuations can be explained by fluctuations of the magnetization directions of small interacting grains within the particles.
Keywords
goethite (α-FeOOH); Mössbauer spectroscopy; magnetic relaxation; nanoparticles
Hrčak ID:
153941
URI
Publication date:
31.12.2015.
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