Surface Magnetism of α-FeO(OH) and β-FeO(OH) by Mössbauer Spectroscopy

Autor:	Masao Kiyama, Torayuki Honmyo, Teruya Shinjo, Akinori Yamamoto
Rok vydání:	1994
Předmět:	Surface (mathematics) Nuclear magnetic resonance Materials science Mössbauer effect Isotope Magnetism Mössbauer spectroscopy Analytical chemistry General Physics and Astronomy Surface layer Hyperfine structure Ion
Zdroj:	Journal of the Physical Society of Japan. 63:176-183
ISSN:	1347-4073 0031-9015
DOI:	10.1143/jpsj.63.176
Popis:	Fine particles of α-FeO(OH) and β-FeO(OH) were prepared using 56 Fe isotope and the surfaces of the particles were coated with extremely thin 57 Fe(III) layers. Mossbauer results show that the Fe(III) ions in the top surface layer are involved in the magnetic order and the surface hyperfine fields rapidly decrease with increasing temperature. The exchange fields at surface sites, estimated from the temperature dependences of the hyperfine fields, are smaller than the bulk values in both cases. The decrease of exchange fields at the surface sites corresponds to the reduced number of neighboring magnetic ions at each site.
Databáze:	OpenAIRE
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