Iron mixed-valence compounds, BaSm(Cu0.5+xFe0.5-x)2O5+δ. II: the Fe2.5+ state and magnetic properties

J. Lindén*, J. Nakamura, T. Pietari, T. Taniyama, M. Karppinen, H. Yamauchi

*Tämän työn vastaava kirjoittaja

Tutkimustuotos: LehtiartikkeliKonferenssiartikkeliTieteellinenvertaisarvioitu

Abstrakti

Recently, a fluctuating mixed-valence state formally denoted as Fe2.5+ was observed in BaSmFe2O5+δ double-perovskite samples, having δ < 0.5 [J. Linden, P. Karen, A. Kjekshus, J. Miettinen, T. Pietari, M. Karppinen, Phys. Rev. B 60 (1999) 15251.]. Upon cooling such samples to the Verwey-type transition temperature (TV ≈ 200 K), a mixing-separation transition of the valence state occurs. In order to study in detail the formation of the mixed-valence state BaSm(Cu0.5+xFe0.5-x)2O5+δ, samples with a certain amount of Fe (0-10% and 40-50%) replaced by Cu have been characterized by 57Fe Mossbauer spectroscopy and magnetization measurements. All samples were found to be magnetically ordered at room temperature. The amount of Fe entering the Fe2.5+ state decreased rapidly as the Cu doping level was increased, as judged by the Mossbauer spectra. Increasing the Cu concentration also led to an increase of TV.

AlkuperäiskieliEnglanti
Sivut126-131
Sivumäärä6
JulkaisuPhysica C: Superconductivity and its Applications
Vuosikerta338
Numero1
DOI - pysyväislinkit
TilaJulkaistu - 1 elokuuta 2000
OKM-julkaisutyyppiA4 Artikkeli konferenssijulkaisuussa
TapahtumaInternational Discussion Meeting on Chemistry Approaches to High-Tc Superconductive Materials / 5th International Workshop on Chemical Designing and Processing of High-Tc Superconductors (Chem-HTSC-V) - Yokohama, Jpn
Kesto: 15 lokakuuta 199916 lokakuuta 1999

Sormenjälki Sukella tutkimusaiheisiin 'Iron mixed-valence compounds, BaSm(Cu<sub>0.5+x</sub>Fe<sub>0.5-x</sub>)<sub>2</sub>O<sub>5+δ</sub>. II: the Fe<sup>2.5+</sup> state and magnetic properties'. Ne muodostavat yhdessä ainutlaatuisen sormenjäljen.

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