Eight rare-earth-substituted Pb-based 1:2:1:2 superconducting compounds: (Pb,Cu)Sr sub 2 (Ca, R )Cu sub 2 O sub 7 ( R =Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm)

Journal Article · Sun Sep 01 00:00:00 EDT 1991 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.44.5369· OSTI ID:5293816

Liu, H B; Morris, D E ^[1]

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1. Morris Research Incorporated, 1918 University Avenue, Berkeley, California (USA)

Rare-earth substitution has given a series of Pb-based 1:2:1:2 superconducting compounds (Pb,Cu)Sr{sub 2}(Ca,{ital R})Cu{sub 2}O{sub 7} ({ital R}=Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm). {ital T}{sub {ital c}}'s vary inversely with rare-earth ionic size from 72 K (Tm) to 60 K (Gd) and then remain constant for larger ions up to Nd. This behavior ({ital T}{sub {ital c}} decreasing for larger ions separating the two CuO{sub 2} superconducting sheets) is similar to the behavior of RBa{sub 2}Cu{sub 4}O{sub 8} (1:2:4) and {ital R}{sub 2}Ba{sub 4}Cu{sub 7}O{sub {ital y}} (2:4:7), but not {ital R}Ba{sub 2}Cu{sub 3}O{sub 7} (1:2:3). As prepared in air the samples were not superconductors; superconductivity was induced by annealing in oxygen under 100 bar of oxygen pressure at 940 {degree}C followed by fast cooling from 940 to 100 {degree}C (50 {degree}C/min). Lattice constants of the compounds correlate with the ionic radii of the rare-earth elements, as in the 1:2:3, 1:2:4, and 2:4:7 compounds.

• OSTI ID: 5293816
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 44:10; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CALCIUM OXIDES
SYNTHESIS
COPPER OXIDES
DYSPROSIUM OXIDES
ERBIUM OXIDES
EUROPIUM OXIDES
GADOLINIUM OXIDES
HOLMIUM OXIDES
LEAD OXIDES
NEODYMIUM OXIDES
SAMARIUM OXIDES
STRONTIUM OXIDES
TERBIUM OXIDES
ANNEALING
HIGH-TC SUPERCONDUCTORS
LATTICE PARAMETERS
TRANSITION TEMPERATURE
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
DYSPROSIUM COMPOUNDS
ERBIUM COMPOUNDS
EUROPIUM COMPOUNDS
GADOLINIUM COMPOUNDS
HEAT TREATMENTS
HOLMIUM COMPOUNDS
LEAD COMPOUNDS
NEODYMIUM COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
SAMARIUM COMPOUNDS
STRONTIUM COMPOUNDS
SUPERCONDUCTORS
TERBIUM COMPOUNDS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties