Moessbauer studies of ultrafine iron-containing particles on a carbon support

F. Boedker; S. Moerup; C.A. Oxborrow; S. Linderoth; M.B. Madsen; J.W. Niemantsverdriet

doi:10.1088/0953-8984/4/31/008

Moessbauer studies of ultrafine iron-containing particles on a carbon support

F. Boedker, S. Moerup, C.A. Oxborrow, S. Linderoth, M.B. Madsen, J.W. Niemantsverdriet

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Abstract

Carbon-supported metallic iron particles with an av. diam. of 3.7 nm have been studied in situ by Moessbauer spectroscopy in the temp. range 5-305 K and with external magnetic fields up to 4 T. Depending on the prepn. conditions various amts. of amorphous Fe-C particles are also formed. The av. magnetic hyperfine fields of the surface atoms of a-Fe particles are significantly larger than that of bulk a-Fe at 5 K, but decrease much faster with increasing temp. than the bulk hyperfine field. The superparamagnetic blocking temp. for the a-Fe particles is about 70 K, but after oxidn. it decreases to about 50 K, indicating that the magnetic anisotropy energy const. of the oxidized particles is significantly lower than that of the metallic particles. The temp. dependence of the spectral area is similar in the metallic and the oxidized states. In both cases the vibrational modes are dominated by particle vibrations. [on SciFinder (R)]

Original language	English
Pages (from-to)	6555-6568
Journal	Journal of Physics : Condensed Matter
Volume	4
Issue number	31
DOIs	https://doi.org/10.1088/0953-8984/4/31/008
Publication status	Published - 1992

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title = "Moessbauer studies of ultrafine iron-containing particles on a carbon support",

abstract = "Carbon-supported metallic iron particles with an av. diam. of 3.7 nm have been studied in situ by Moessbauer spectroscopy in the temp. range 5-305 K and with external magnetic fields up to 4 T. Depending on the prepn. conditions various amts. of amorphous Fe-C particles are also formed. The av. magnetic hyperfine fields of the surface atoms of a-Fe particles are significantly larger than that of bulk a-Fe at 5 K, but decrease much faster with increasing temp. than the bulk hyperfine field. The superparamagnetic blocking temp. for the a-Fe particles is about 70 K, but after oxidn. it decreases to about 50 K, indicating that the magnetic anisotropy energy const. of the oxidized particles is significantly lower than that of the metallic particles. The temp. dependence of the spectral area is similar in the metallic and the oxidized states. In both cases the vibrational modes are dominated by particle vibrations. [on SciFinder (R)]",

author = "F. Boedker and S. Moerup and C.A. Oxborrow and S. Linderoth and M.B. Madsen and J.W. Niemantsverdriet",

year = "1992",

doi = "10.1088/0953-8984/4/31/008",

language = "English",

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T1 - Moessbauer studies of ultrafine iron-containing particles on a carbon support

AU - Boedker, F.

AU - Moerup, S.

AU - Oxborrow, C.A.

AU - Linderoth, S.

AU - Madsen, M.B.

AU - Niemantsverdriet, J.W.

PY - 1992

Y1 - 1992

N2 - Carbon-supported metallic iron particles with an av. diam. of 3.7 nm have been studied in situ by Moessbauer spectroscopy in the temp. range 5-305 K and with external magnetic fields up to 4 T. Depending on the prepn. conditions various amts. of amorphous Fe-C particles are also formed. The av. magnetic hyperfine fields of the surface atoms of a-Fe particles are significantly larger than that of bulk a-Fe at 5 K, but decrease much faster with increasing temp. than the bulk hyperfine field. The superparamagnetic blocking temp. for the a-Fe particles is about 70 K, but after oxidn. it decreases to about 50 K, indicating that the magnetic anisotropy energy const. of the oxidized particles is significantly lower than that of the metallic particles. The temp. dependence of the spectral area is similar in the metallic and the oxidized states. In both cases the vibrational modes are dominated by particle vibrations. [on SciFinder (R)]

AB - Carbon-supported metallic iron particles with an av. diam. of 3.7 nm have been studied in situ by Moessbauer spectroscopy in the temp. range 5-305 K and with external magnetic fields up to 4 T. Depending on the prepn. conditions various amts. of amorphous Fe-C particles are also formed. The av. magnetic hyperfine fields of the surface atoms of a-Fe particles are significantly larger than that of bulk a-Fe at 5 K, but decrease much faster with increasing temp. than the bulk hyperfine field. The superparamagnetic blocking temp. for the a-Fe particles is about 70 K, but after oxidn. it decreases to about 50 K, indicating that the magnetic anisotropy energy const. of the oxidized particles is significantly lower than that of the metallic particles. The temp. dependence of the spectral area is similar in the metallic and the oxidized states. In both cases the vibrational modes are dominated by particle vibrations. [on SciFinder (R)]

U2 - 10.1088/0953-8984/4/31/008

DO - 10.1088/0953-8984/4/31/008

M3 - Article

VL - 4

SP - 6555

EP - 6568

JO - Journal of Physics : Condensed Matter

JF - Journal of Physics : Condensed Matter

SN - 0953-8984

IS - 31

ER -

Moessbauer studies of ultrafine iron-containing particles on a carbon support

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