On phase equilibria and crystal structures in the systems Ce-Pd-B and Yb-Pd-B. Physical properties of R{sub 2}Pd{sub 13.6}B{sub 5} (R=Yb, Lu)

Journal Article · Sat May 15 04:00:00 EDT 2010 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2010.02.016· OSTI ID:21372587

Sologub, Oksana ^[1]; Rogl, Peter ^[1]; Salamakha, Leonid; Bauer, Ernst; Hilscher, Gerfried; Michor, Herwig ^[2]; Giester, Gerald ^[3]

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1. Institute of Physical Chemistry, University of Vienna, A-1090 Wien, Waehringerstrasse 42 (Austria)
2. Institute of Solid State Physics, Vienna University of Technology, A-1040 Wien (Austria)
3. Institute of Mineralogy and Crystallography, University of Vienna, Althanstr. 14, A-1090 Wien (Austria)

Phase equilibria and crystal structures of ternary compounds were determined in the systems Ce-Pd-B and Yb-Pd-B at 850 deg. C in the concentration ranges up to 45 and 33 at% of Ce and Yb, respectively, employing X-ray single crystal and powder diffraction. Phase relations in the Ce-Pd-B system at 850 deg. C are governed by formation of extended homogeneity fields, tau{sub 2}-CePd{sub 8}B{sub 2-x} (0.10<x<0.48); tau{sub 3}-Ce{sub 3}Pd{sub 25-x}B{sub 8-y} (1.06<x<1.87; 2.20<y<0.05), and CePd{sub 3}B{sub x} (0<x<0.65) the latter arising from binary CePd{sub 3}. Crystallographic parameters for the new structure type tau{sub 2}-CePd{sub 8}B{sub 2-x} (space group C2/c, a=1.78104(4) nm, b=1.03723(3) nm, c=1.16314(3), beta=118.515(1){sup o} for x=0.46) were established from X-ray single crystal diffraction. The crystal structures of tau{sub 2}-CePd{sub 8}B{sub 2-x} and tau{sub 3}-Ce{sub 3}Pd{sub 25-x}B{sub 3-y} are connected in a crystallographic group-subgroup relationship. Due to the lack of suitable single crystals, the novel structure of tau{sub 1}-Ce{sub 6}Pd{sub 47-x}B{sub 6} (x=0.2, C2/m space group, a=1.03594(2) nm, b=1.80782(3) nm, c=1.01997(2) nm, beta=108.321(1){sup o}) was determined from Rietveld refinement of X-ray powder diffraction data applying the structural model obtained from single crystals of homologous La{sub 6}Pd{sub 47-x}B{sub 6} (x=0.19) (X-ray single crystal diffraction, new structure type, space group C2/m, a=1.03988(2) nm, b=1.81941(5) nm, c=1.02418(2) nm, beta=108.168(1){sup o}). The Yb-Pd-B system is characterized by one ternary compound, tau{sub 1}-Yb{sub 2}Pd{sub 14}B{sub 5}, forming equilibria with extended solution YbPd{sub 3}B{sub x}, YbB{sub 6}, Pd{sub 5}B{sub 2} and Pd{sub 3}B. The crystal structures of both Yb{sub 2}Pd{sub 14}B{sub 5} and isotypic Lu{sub 2}Pd{sub 14}B{sub 5} were determined from X-ray Rietveld refinements and found to be closely related to the Y{sub 2}Pd{sub 14}B{sub 5}-type (I4{sub 1}/amd). The crystal structure of binary Yb{sub 5}Pd{sub 2-x} (Mn{sub 5}C{sub 2}-type) was confirmed from X-ray single crystal data and a slight defect on the Pd site (x=0.06) was established. The three structures tau{sub 1}-Ce{sub 6}Pd{sub 47-x}B{sub 6}, tau{sub 2}-CePd{sub 8}B{sub 2-x} and tau{sub 3}-Ce{sub 3}Pd{sub 25-x}B{sub 8-y} are related and can be considered as the packings of fragments observed in Nd{sub 2}Fe{sub 14}B structure with different stacking of common structural blocks. Physical properties for Yb{sub 2}Pd{sub 13.6}B{sub 5} (temperature dependent specific heat, electrical resistivity and magnetization) yielded a predominantly Yb-4f{sup 13} electronic configuration, presumably related with a magnetic instability below 2 K. Kondo interaction and crystalline electric field effects control the paramagnetic temperature domain. - Graphical Abstract: Crystal structure of CePd{sub 8}B{sub 2-x}.

• OSTI ID: 21372587
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 5 Vol. 183; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ALLOYS
BORON ALLOYS
CERIUM ALLOYS
COHERENT SCATTERING
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTALLOGRAPHY
CRYSTALS
DIAGRAMS
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRONIC STRUCTURE
INFORMATION
INTERMETALLIC COMPOUNDS
LUTETIUM ALLOYS
MAGNETISM
MONOCLINIC LATTICES
MONOCRYSTALS
PALLADIUM ALLOYS
PARAMAGNETISM
PHASE DIAGRAMS
PHYSICAL PROPERTIES
PLATINUM METAL ALLOYS
RARE EARTH ALLOYS
SCATTERING
SPACE GROUPS
SPECIFIC HEAT
STRUCTURAL MODELS
SYMMETRY GROUPS
TEMPERATURE DEPENDENCE
TETRAGONAL LATTICES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT ALLOYS
X-RAY DIFFRACTION