Metallic properties of Ba{sub 2}Cu{sub 3}P{sub 4} and BaCu{sub 2}Pn{sub 2} (Pn=As, Sb)

Journal Article · Sun Jul 15 04:00:00 EDT 2012 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2012.03.036· OSTI ID:22012194

Saparov, Bayrammurad ^[1]; Sefat, Athena S ^[1]

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1. Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

We report the synthesis of ternary barium copper pnictides, Ba{sub 2}Cu{sub 3}P{sub 4} and BaCu{sub 2}Pn{sub 2} (Pn=As, Sb), and their structural, magnetic, and transport properties. They all crystallize in different structures shown by X-ray diffraction, although their structures reveal close relations. The body-centered tetragonal BaCu{sub 2}As{sub 2} adopts ThCr{sub 2}Si{sub 2}-type (I4/mmm) structure, whereas Ba{sub 2}Cu{sub 3}P{sub 4} is a copper-deficient derivative of this phase, crystallizing in the body-centered orthorhombic space group, Ibam. There are two polymorphs of BaCu{sub 2}Sb{sub 2}: {alpha}-BaCu{sub 2}Sb{sub 2} that adopts CaBe{sub 2}Ge{sub 2}-type structure; {beta}-BaCu{sub 2}Sb{sub 2} that is a 2:1 combination of CaBe{sub 2}Ge{sub 2}- and ThCr{sub 2}Si{sub 2}-type structural segments. All phases are metallic and non-magnetic. The room temperature thermal conductivity for polycrystalline BaCu{sub 2}As{sub 2} is Almost-Equal-To 2 W/(m K) and the Seebeck coefficient is Almost-Equal-To 15 {mu}V/K, which result in a small ( Almost-Equal-To 0.03) thermoelectric figure of merit. - Graphical abstract: Ternary copper pnictides of barium Ba{sub 2}Cu{sub 3}P{sub 4} and BaCu{sub 2}Pn{sub 2} (Pn=As, Sb) show metallic and non-magnetic behavior. Highlights: Black-Right-Pointing-Pointer Synthesis of Ba{sub 2}Cu{sub 3}P{sub 4} and BaCu{sub 2}Pn{sub 2} (Pn=As, Sb). Black-Right-Pointing-Pointer A new form of BaCu{sub 2}Sb{sub 2} (CaBe{sub 2}Ge{sub 2}-type) obtained and characterized. Black-Right-Pointing-Pointer The phases are metallic and non-magnetic in agreement with theory. Black-Right-Pointing-Pointer The thermal conductivity and Seebeck coefficient of BaCu{sub 2}As{sub 2} are quite low.

• OSTI ID: 22012194
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Vol. . 191; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
BARIUM
COPPER
ORTHORHOMBIC LATTICES
PNICTIDES
POLYCRYSTALS
SPACE GROUPS
SUPERCONDUCTIVITY
SYNTHESIS
TETRAGONAL LATTICES
THERMAL CONDUCTIVITY
X-RAY DIFFRACTION