Neutron-scattering study of the dynamical spin susceptibility in YBa sub 2 Cu sub 3 O sub 6. 6

Journal Article · Tue Sep 01 04:00:00 EDT 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.46.5561· OSTI ID:7177200

Tranquada, J M; Gehring, P M; Shirane, G ^[1]; Shamoto, S; Sato, M ^[2]

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1. Brookhaven National Laboratory, Upton, New York 11973 (United States)
2. Department of Physics, Nagoya University, Nagoya 464-01 (Japan)

We report a detailed neutron-scattering study of the dynamical spin susceptibility in a single crystal of YBa{sub 2}Cu{sub 3}O{sub 6+{ital x}}, with {ital x}=0.6 and {ital T}{sub {ital c}}=53 K. The measurements cover the energy range from 5 to 50 meV, and temperatures from 10 to 100 K. It is shown that antiferromagnetic correlations between nearest-neighbor CuO{sub 2} layers are quite strong. As a result, only in-phase bilayer spin fluctuations are observed at low energies, with the out-of-phase fluctuations making a weak appearance at 40 meV. Within the two-dimensional (2D) Brillouin zone corresponding to a single layer, the imginary part of the dynamical susceptibility {chi}{prime}{prime}({bold Q},{omega}) exhibits a broad peak about the point corresponding to antiferromagnetic order {bold Q}{sub AF} with a width that is mildly energy dependent. At 10 K, {chi}{prime}{prime}({bold Q}{sub AF},{omega}) has a rather sharp peak near 27 meV; integrating {chi}{prime}{prime} over the 2D magnetic Brillouin zone makes the peak in energy much broader. (We have verified that the falloff at high energies also occurs in a previously studied crystal with {ital x}=0.5, {ital T}{sub {ital c}}=50 K.) Although the amplitude at 5 meV and 10 K is near zero, considerable spectral weight is observed at energies well below the weak-coupling limit for 2{Delta}, where {Delta} is the superconducting gap. The temperature dependence of the 2D {bold Q}-integrated {chi}{prime}{prime} is well described by a simple function containing a temperature-independent energy gap of 9 meV. A study of the {bold Q} dependence of {chi}{prime}{prime} at {h bar}{omega}=15 meV indicates that the signal falls off rather abruptly on moving away from {bold Q}{sub AF} (compared to a simple Gaussian distribution). Measurements along two different directions in the 2D zone suggest that the width of the distribution about {bold Q}{sub AF} is anisotropic.

• OSTI ID: 7177200
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 46:9; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
ALKALINE EARTH METAL COMPOUNDS
ANTIFERROMAGNETISM
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COHERENT SCATTERING
COPPER COMPOUNDS
COPPER OXIDES
CRYSTALS
DIFFRACTION
ENERGY RANGE
EV RANGE
FLUCTUATIONS
HIGH-TC SUPERCONDUCTORS
MAGNETISM
MILLI EV RANGE
MONOCRYSTALS
NEUTRON DIFFRACTION
OXIDES
OXYGEN COMPOUNDS
SCATTERING
SUPERCONDUCTORS
TEMPERATURE RANGE
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TRANSITION ELEMENT COMPOUNDS
VARIATIONS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES