Order-disorder transition and valence state of ytterbium in YbAu{sub x}Ga{sub 2-x} (0.26<=x<=1.31)

Journal Article · Mon Dec 14 23:00:00 EST 2009 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2009.09.015· OSTI ID:21372434

Gumeniuk, R ^[1]; Bischoff, E ^[2]; Burkhardt, U; Prots, Yu; Schnelle, W ^[1]; Vasylechko, L ^[3]; Schmidt, M ^[1]; Kuzma, Yu ^[4]; Grin, Yu ^[1]

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1. Max-Planck-Institut fuer Chemische Physik fester Stoffe, Noethnitzer Str. 40, 01187 Dresden (Germany)
2. Max-Planck-Institut fuer Metallforschung, Heisenbergstr. 3, 70569 Stuttgart (Germany)
3. Lviv Polytechnic National University, Bandera Str. 12, 79013 Lviv (Ukraine)
4. Department of Analytical Chemistry, Ivan Franko National University of Lviv, Kyryla and Mefodija Str. 6, 79005 Lviv (Ukraine)

The intermetallic compounds YbAu{sub x}Ga{sub 2-x} (0.26<=x<=1.31) were synthesized by melting of elemental components and subsequent annealing. The crystal structure of YbAu{sub 1.04}Ga{sub 0.96} was investigated using single-crystal X-ray diffraction data: structure type TiNiSi, space group Pnma, a=7.1167(3) A, b=4.5019(3) A, c=7.7083(3) A, R{sub F}=0.028 for 27 variables and 441 reflections. At 600 deg. C this compound is described as partially substituted TiNiSi type and shows a homogeneity range around the equiatomic composition YbAu{sub x}Ga{sub 2-x} (0.94<=x<=1.19). For the gallium- (0.26<=x<=0.83) and gold-rich (1.21<=x<=1.31) regions, the KHg{sub 2} type of crystal structure (space group Imma) with mixed Au/Ga occupation is found. A temperature-driven phase transition for the composition YbAuGa from ordered TiNiSi to disordered KHg{sub 2} structure type is observed at 629 deg. C. Yb L{sub III} X-ray absorption spectra indicate an intermediate valence of +2.5 for Yb atoms in YbAuGa. For samples deviating from this composition a further reduced valence of Yb is observed. Magnetic susceptibility studies show a non-magnetic 4f{sup 14} ground state of Yb atoms with thermal fluctuations towards the 4f{sup 13} state. - Graphical abstract: Ordering of the crystal structure in the YbAu{sub x}Ga{sub 2-x} is accompanied by the change of valence of Yb atoms.

• OSTI ID: 21372434
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 12 Vol. 182; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ABSORPTION SPECTROSCOPY
ALLOYS
ANNEALING
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTALS
DIFFRACTION
ENERGY LEVELS
GALLIUM ALLOYS
GOLD ALLOYS
GROUND STATES
HEAT TREATMENTS
INTERMETALLIC COMPOUNDS
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
MAGNETISM
MELTING
MONOCRYSTALS
ORDER-DISORDER TRANSFORMATIONS
ORTHORHOMBIC LATTICES
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
RARE EARTH ALLOYS
SCATTERING
SPACE GROUPS
SPECTRA
SPECTROSCOPY
SYMMETRY GROUPS
TEMPERATURE RANGE
TEMPERATURE RANGE 0400-1000 K
TETRAGONAL LATTICES
TRANSITION ELEMENT ALLOYS
VALENCE
X-RAY DIFFRACTION
X-RAY SPECTRA
X-RAY SPECTROSCOPY
YTTERBIUM ALLOYS