Ternary aluminides R{sub 0.67}Ni{sub 2}Al{sub 6} (R=Sc, Y, Gd-Lu) with partly disordered structures

Journal Article · Fri Feb 15 04:00:00 EST 2013 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2012.09.031· OSTI ID:22149997

Matselko, Oksana; Pukas, Svitlana; Lutsyshyn, Yuriy ^[1]; Gladyshevskii, Roman ^[1]; Kaczorowski, Dariusz ^[2]

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1. Department of Inorganic Chemistry, Ivan Franko National University of Lviv, Kyryla i Mefodiya St. 6, 79005 Lviv (Ukraine)
2. Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland)

Ten rare-earth nickel aluminides R{sub 0.67}Ni{sub 2}Al{sub 6} (R=Sc, Y, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) were synthesized by arc melting and their crystal structures studied by X-ray powder diffraction. They crystallize in the hexagonal structure type Yb{sub 0.67}Ni{sub 2}Al{sub 6}: Pearson symbol hP11-2.33, space group P-6m2, a=4.18904(2), c=9.09816(6) A, which can be decomposed into three kinds of layer. The sequence of layers along [001] is Yb{sub 0.67}Al-NiAl{sub 2}-Al-NiAl{sub 2}, but stacking faults appear due to relative shifts of consecutive Yb{sub 0.67}Al layers containing two rare-earth metal atoms for one Al-atom triangle. An ordered superstructure is the type ErNi{sub 3}Al{sub 9} (Pearson symbol hR78, space group R32, a={radical}(3)a{sub 0}, c=3c{sub 0}), refined on single crystals. The physical properties of the R{sub 0.67}Ni{sub 2}Al{sub 6} (R=Tb, Er, Tm, Yb, and Lu) compounds were determined by means of magnetic and electrical transport measurements. All these materials but Lu{sub 0.67}Ni{sub 2}Al{sub 6} exhibit Curie-Weiss paramagnetic behavior due to the trivalent R ions, and order magnetically at low temperatures. They show good metallic conductivity. The Yb-containing compound is a dense Kondo system with distinct features in the paramagnetic state of the interplay between Kondo and crystalline electric field interactions. - Graphical abstract: Stacking of layers along [001] in the Yb{sub 0.67}Ni{sub 2}Al{sub 6}-type structure. Highlights: Black-Right-Pointing-Pointer The aluminides R{sub 0.67}Ni{sub 2}Al{sub 6} (R=Sc, Y, Gd-Lu) adopt a partly disordered structure. Black-Right-Pointing-Pointer The structure is characterized by R{sub 2}Al{sub 3} layers with two R atoms for one Al{sub 3} triangle. Black-Right-Pointing-Pointer The compounds with R=Tb, Er, Tm are paramagnets at rt and order magnetically at lt. Black-Right-Pointing-Pointer The Yb-compound exhibits a magnetically ordered Kondo lattice with strong CEF effect.

• OSTI ID: 22149997
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Vol. 198; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ELECTRIC FIELDS
ELECTRICAL PROPERTIES
INTERACTIONS
LAYERS
MAGNETIC PROPERTIES
MONOCRYSTALS
NICKEL
PARAMAGNETISM
RARE EARTHS
SPACE GROUPS
STACKING FAULTS
TRIGONAL LATTICES
X-RAY DIFFRACTION
YTTERBIUM COMPOUNDS