Anomalous phenomenology in nickel substituted cuprates

Journal Article · Sat Oct 01 00:00:00 EDT 1994 · Materials Research Bulletin; (United States)

DOI:https://doi.org/10.1016/0025-5408(94)90083-3· OSTI ID:7154518

Ko, D; Oesterreicher, H ^[1]

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1. Univ. of California, San Diego, La Jolla, CA (United States). Materials Science and Dept. of Chemistry

The authors present structural, magnetic, and superconducting behaviors for YBa[sub 2](Cu[sub 1[minus]x]Ni[sub x])[sub 3]O[sub y] with emphasis on x = 0.05 given various thermal redox sequencings. They demonstrate that materials quenched from various air annealing temperatures display an unusual extension of the orthorhombic regime compared to unsubstituted materials. In the range of annealing temperature near 970 K, this is accompanied by volume expansion anomalies and slow reoxygenation kinetics probably connected with partial 3+ charge localization on Cu. A second volume expansion anomaly occurs near 1,080 K, probably connected with partial 3+ charge localization on Ni. These materials can show diamagnetism up to 150K, possibly indicating a small amount of superconductivity. On reoxygenation at 673K materials undergo a slow transition, first to a paramagnetic-semiconducting state (designed K[sub o] compounds) and then after several days to a superconducting state similar to conventionally slow cooled oxygenating preparations (OP) which produce [Tc] [approximately] 74 K. These superconductors display anomalous Meissner effects, i.e. the observation of paramagnetism below [Tc] on small field cooling. This effect is connected with flux trapping in 2 types of regions, namely grain boundaries or local cluster inhomogeneities of the bulk.

• OSTI ID: 7154518
• Journal Information: Materials Research Bulletin; (United States), Vol. 29:10; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BARIUM OXIDES
CRYSTAL STRUCTURE
PHYSICAL PROPERTIES
COPPER OXIDES
NICKEL OXIDES
YTTRIUM OXIDES
HIGH-TC SUPERCONDUCTORS
TRANSITION TEMPERATURE
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
CHALCOGENIDES
COPPER COMPOUNDS
NICKEL COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SUPERCONDUCTORS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
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