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Title: On the structural and magnetic properties of the ternary silicides Ce{sub 6} M {sub 1.67}Si{sub 3} (M=Co, Ni) and Ce{sub 5}Ni{sub 1.85}Si{sub 3}

Abstract

Contrary to that reported previously, the ternary silicide 'Ce{sub 6}Ni{sub 2}Si{sub 3}' does not exist. The melting of this alloy, followed or not by annealing, leads to the existence of the two new ternary compounds, Ce{sub 6}Ni{sub 1.67}Si{sub 3} and Ce{sub 5}Ni{sub 1.85}Si{sub 3}. The investigation of these ternary silicides based on nickel and Ce{sub 6}Co{sub 1.67}Si{sub 3} by X-ray diffraction on single crystal reveals an ordered distribution between Ni (or Co) and Si atoms. The nickel or cobalt positions in the chains of face-shared octahedra of cerium are not fully occupied with a strong delocalisation of their electron density. The structural investigations of these compounds confirm that the 'Ce{sub 6}Ni{sub 2}Si{sub 3}' and 'Ce{sub 5}Ni{sub 2}Si{sub 3}' structural type have to be rewritten as Ce{sub 6}Ni{sub 2-} {sub x} Si{sub 3} and Ce{sub 5}Ni{sub 2-} {sub x} Si{sub 3}. Magnetisation and specific heat measurements evidence a magnetic ordering at 3.8(2) K for Ce{sub 6}Ni{sub 1.67}Si{sub 3} and a heavy fermion behaviour for Ce{sub 6}Co{sub 1.67}Si{sub 3}. - Graphical abstract: Projection along the c-axis of the structure of Ce{sub 6}Co{sub 1.67}Si{sub 3}. A strong delocalisation of cobalt atoms is observed in the chains of cerium octahedra.

Authors:
 [1];  [2]
  1. Institut de Chimie de la Matiere Condensee de Bordeaux (ICMCB), CNRS (UPR 9048), Universite Bordeaux 1, 87 Avenue du Docteur A. Schweitzer, 33608 Pessac Cedex (France), E-mail: gaudin@icmcb-bordeaux.cnrs.fr
  2. Institut de Chimie de la Matiere Condensee de Bordeaux (ICMCB), CNRS (UPR 9048), Universite Bordeaux 1, 87 Avenue du Docteur A. Schweitzer, 33608 Pessac Cedex (France)
Publication Date:
OSTI Identifier:
21015789
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 4; Other Information: DOI: 10.1016/j.jssc.2007.01.030; PII: S0022-4596(07)00063-1; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANNEALING; CERIUM SILICIDES; COBALT SILICIDES; CRYSTAL STRUCTURE; ELECTRON DENSITY; MAGNETIC PROPERTIES; MAGNETIZATION; MELTING; MONOCRYSTALS; NICKEL SILICIDES; SPECIFIC HEAT; X-RAY DIFFRACTION

Citation Formats

Gaudin, E., and Chevalier, B.. On the structural and magnetic properties of the ternary silicides Ce{sub 6} M {sub 1.67}Si{sub 3} (M=Co, Ni) and Ce{sub 5}Ni{sub 1.85}Si{sub 3}. United States: N. p., 2007. Web. doi:10.1016/j.jssc.2007.01.030.
Gaudin, E., & Chevalier, B.. On the structural and magnetic properties of the ternary silicides Ce{sub 6} M {sub 1.67}Si{sub 3} (M=Co, Ni) and Ce{sub 5}Ni{sub 1.85}Si{sub 3}. United States. doi:10.1016/j.jssc.2007.01.030.
Gaudin, E., and Chevalier, B.. Sun . "On the structural and magnetic properties of the ternary silicides Ce{sub 6} M {sub 1.67}Si{sub 3} (M=Co, Ni) and Ce{sub 5}Ni{sub 1.85}Si{sub 3}". United States. doi:10.1016/j.jssc.2007.01.030.
@article{osti_21015789,
title = {On the structural and magnetic properties of the ternary silicides Ce{sub 6} M {sub 1.67}Si{sub 3} (M=Co, Ni) and Ce{sub 5}Ni{sub 1.85}Si{sub 3}},
author = {Gaudin, E. and Chevalier, B.},
abstractNote = {Contrary to that reported previously, the ternary silicide 'Ce{sub 6}Ni{sub 2}Si{sub 3}' does not exist. The melting of this alloy, followed or not by annealing, leads to the existence of the two new ternary compounds, Ce{sub 6}Ni{sub 1.67}Si{sub 3} and Ce{sub 5}Ni{sub 1.85}Si{sub 3}. The investigation of these ternary silicides based on nickel and Ce{sub 6}Co{sub 1.67}Si{sub 3} by X-ray diffraction on single crystal reveals an ordered distribution between Ni (or Co) and Si atoms. The nickel or cobalt positions in the chains of face-shared octahedra of cerium are not fully occupied with a strong delocalisation of their electron density. The structural investigations of these compounds confirm that the 'Ce{sub 6}Ni{sub 2}Si{sub 3}' and 'Ce{sub 5}Ni{sub 2}Si{sub 3}' structural type have to be rewritten as Ce{sub 6}Ni{sub 2-} {sub x} Si{sub 3} and Ce{sub 5}Ni{sub 2-} {sub x} Si{sub 3}. Magnetisation and specific heat measurements evidence a magnetic ordering at 3.8(2) K for Ce{sub 6}Ni{sub 1.67}Si{sub 3} and a heavy fermion behaviour for Ce{sub 6}Co{sub 1.67}Si{sub 3}. - Graphical abstract: Projection along the c-axis of the structure of Ce{sub 6}Co{sub 1.67}Si{sub 3}. A strong delocalisation of cobalt atoms is observed in the chains of cerium octahedra.},
doi = {10.1016/j.jssc.2007.01.030},
journal = {Journal of Solid State Chemistry},
number = 4,
volume = 180,
place = {United States},
year = {Sun Apr 15 00:00:00 EDT 2007},
month = {Sun Apr 15 00:00:00 EDT 2007}
}
  • After melting and quenching, the ternary silicides U[sub 2]Fe[sub 17[minus]y]Si[sub y] exist for 3.3 [le] y [le] 4.5 but they partially decompose after annealing at 850-900[degrees]C. Their crystal structure, determined by X-ray diffractometry on both single crystals and powder, derives from the hexagonal Th[sub 2]Ni[sub 17]-type but depends strongly on the silicon content. For y = 3.7 some uranium sites are partially replaced by pairs of iron atoms and conversely. This structure shows some similarities to that observed for the binary compound Ho[sub 2]Fe[sub 17]. On the other hand, for y = 4.2, all the uranium atoms and pairs ofmore » iron atoms are statistically distributed. In contrast, the ternary silicide U[sub 2]Co[sub 15]Si[sub 2], which is obtained as single phase after annealing at 850[degrees]C, adopts the Th[sub 2]Ni[sub 17]-type structure. In all compounds, iron or cobalt atoms of the pair are never substituted by silicon atoms. 13 refs., 6 figs., 4 tabs.« less
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