Crystal-chemical anomalies in nonsuperconducting PrBa[sub 2]Cu[sub 3]O[sub 7]

Conference · Tue Feb 01 04:00:00 EST 1994 · Journal of Superconductivity; (United States)

OSTI ID:7020782

Vanderah, T A; Lowe-Ma, C K ^[1]

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1. Naval Air Warfare Centre Weapons Division, China Lake, CA (United States)

Studies of the crystal chemistry of nonsuperconducting PrBa[sub 2]Cu[sub 3]O[sub 7] indicate that this compound is strictly isostructural with its superconducting RBa[sub 2]Cu[sub 3]O[sub 7] (R - Y, rare earth) analogs. Crystallographically, Pr is present in the trivalent state according to the structural trends exhibited by the RBa[sub 2]Cu[sub 3]O[sub 7] series as a function of R[sup 3+] ionic radius. The sole structural anomaly attributable to the presence of Pr[sup 3+] in the YBa[sub 2]Cu[sub 3]O[sub 7] structure is a next-next-nearest neighbor effect and consists of an unusually short axial Cu-O distance, i.e., a short bond length between the in-plane copper and the chain oxygen. The correlation of this anomaly with the nonmetallic/nonsuperconducting properties of PrBa[sub 2]Cu[sub 3]O[sub 7] supports a variety of literature reports, both theoretical and experimental, suggesting that the apical oxygen in the YBa[sub 2]Cu[sub 3]O[sub 7] structure plays a critical role in mediating the appearance of superconductivity. The mechanism by which the f-electrons in Pr[sup 3+] (f[sup 2]) interact with the Cu-O manifold to produce the nonmetallic behavior of PrBa[sub 2]Cu[sub 3]O[sub 7] remains unknown: however, superconductivity is [open quotes]turned back on[close quotes] for Nd[sup 3+] (f[sup 3]), immediately next to Pr and just slightly smaller. 46 refs., 5 figs.

• OSTI ID: 7020782
• Report Number(s): CONF-930710--
• Conference Information: Journal Name: Journal of Superconductivity; (United States) Journal Volume: 7:1
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
360207 -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CERAMICS
CHALCOGENIDES
CHEMICAL BONDS
COPPER COMPOUNDS
CRYSTALLOGRAPHY
CUPRATES
ELECTRONIC STRUCTURE
HYBRIDIZATION
NEODYMIUM COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PRASEODYMIUM COMPOUNDS
RARE EARTH COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
VALENCE