Investigation of Mixed Valence State of Sm_{1-x}B_{6} and Sm_{1-x}La_{x}B_{6} by XANES

• Authors: S. Gabáni , K. Flachbart , J. Bednarčík , E. Welter , V. Filipov , N. Shitsevalova
• Languages of publication: EN

Abstracts

EN

We investigated the valence states of samarium ions in Sm deficient Sm_{1-x}B_{6} (x=0.03, 0.05, 0.08, 0.1 and 0.2) sintered samples, in single crystalline solid solutions Sm_{1-x}La_{x}B_{6} (x=0.16, 0.28, 0.4, 0.55 and 0.7) as well as in a SmB_{6} single crystal by X-ray absorption near edge structure (XANES) between 4.2 and 300 K. It was shown that the mixed valence state v_{Sm} of Sm-ions (v_{Sm} ≈ 2.51 for SmB_{6} at 4.2 K) in deficient samples is changed but maintained up to a concentration of 20% of vacancies and up to a concentration of 70% in samples doped with trivalent La-ions, and that in both cases it increases with temperature. On the other hand, the value of v_{Sm} increases with increasing vacancy level, whereas it decreases with increasing La^{3+} substitution. The obtained dependences of Sm-valence in SmB_{6} on vacancy as well as on La^{3+} ion concentration are in good agreement with susceptibility measurements and exact numerical calculation of the spinless Falicov-Kimball model in two dimensions.

Keywords

EN

78.70.Dm; 71.28.+d; 71.27.+a

Discipline

• 78.70.Dm: X-ray absorption spectra
• 71.27.+a: Strongly correlated electron systems; heavy fermions
• 71.28.+d: Narrow-band systems; intermediate-valence solids(for magnetic aspects, see 75.20.Hr and 75.30.Mb in magnetic properties and materials)

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 2014
• Volume: 126
• Issue: 1
• Pages: 338-339

Dates

published

2014-07

Contributors

author

S. Gabáni

• Centre of Low Temp. Physics, Institute of Experimental Physics SAS, Watsonova 47, 04001 Košice, Slovakia

author

K. Flachbart

• Centre of Low Temp. Physics, Institute of Experimental Physics SAS, Watsonova 47, 04001 Košice, Slovakia

author

J. Bednarčík

• Deutsches Elektronen Synchrotron DESY, Notkestrasse 85, 22603 Hamburg, Germany

author

E. Welter

• Deutsches Elektronen Synchrotron DESY, Notkestrasse 85, 22603 Hamburg, Germany

author

V. Filipov

• Institute for Problems of Materials Science, NASU, Krzhyzhanovsky 3, 03680 Kiev, Ukraine

author

N. Shitsevalova

• Institute for Problems of Materials Science, NASU, Krzhyzhanovsky 3, 03680 Kiev, Ukraine

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Identifiers

DOI

10.12693/APhysPolA.126.338