sup 139 La NMR study of phase separation in single-crystal La sub 2 CuO sub 4+. delta

Journal Article · Mon Oct 01 00:00:00 EDT 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.42.6781· OSTI ID:6000022

Hammel, P C; Reyes, A P; Fisk, Z; Takigawa, M; Thompson, J D; Heffner, R H; Cheong, S ^[1]; Schirber, J E ^[2]

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1. Los Alamos National Laboratory, Los Alamos, NM (USA)
2. Sandia National Laboratories, Albuquerque, NM (USA)

We report a study of single-crystal La{sub 2}CuO{sub 4+{delta}}, a 38-K superconductor produced by high-pressure oxygenation. We employ {sup 139}La NMR to probe the behavior of copper spins in the CuO{sub 2} planes. At low temperatures we observe two signals, one originating from regions of the crystal rich in oxygen and a second having no excess oxygen ({delta}{approximately}0). Upon warming through 265{plus minus}5 K, the volume fraction of the crystal poor in oxygen goes to zero. The magnetic shift of the peak intensity of the line originating in the oxygen-rich portion of the crystal does not change in the vicinity of 265 K. These observations provide direct microscopic evidence for phase separation in the crystal.

• OSTI ID: 6000022
• Journal Information: Physical Review, B: Condensed Matter; (USA), Vol. 42:10; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
LANTHANUM COMPOUNDS
PHASE STUDIES
CUPRATES
HOLES
LANTHANUM 139
MONOCRYSTALS
NUCLEAR MAGNETIC RESONANCE
SUPERCONDUCTORS
COPPER COMPOUNDS
CRYSTALS
INTERMEDIATE MASS NUCLEI
ISOTOPES
LANTHANUM ISOTOPES
MAGNETIC RESONANCE
NUCLEI
ODD-EVEN NUCLEI
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
RESONANCE
STABLE ISOTOPES
TRANSITION ELEMENT COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties