Mechanical after-effect studies of oxygen relaxation in YBa sub 2 Cu sub 3 O sub 7-. delta

Conference · Tue Jan 01 04:00:00 EST 1991

OSTI ID:5329239

Cost, J R ^[1]; Stanley, J T ^[2]

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1. Los Alamos National Lab., NM (United States)
2. Arizona State Univ., Tempe, AZ (United States)

YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} has an anelastic relaxation involving motion of an oxygen atom or defect. This relaxation has been studied with good agreement by more than seven investigating teams over the temperature range from 200 to 550{degrees}C using internal friction techniques. We have extended measurements of this relaxation to a new regime of temperature and relaxation time using the mechanical after-effect method. Our results cover an additional three orders of magnitude in relaxation time over the temperature range from 50 to 110{degrees}C. The Arrhenius plot, when combined with internal friction results, now covers eleven orders of magnitude in relaxation time. The fit gives an activation energy, Q=1.12 ({plus minus}0.015) and pre-exponential, {tau}{sub 0}=1.9 {times} 10{sup {minus}13} s. The isothermal mechanical relaxation curves we measured always spanned longer times than predicted for a simple exponential relaxation. This indicates that the process is controlled by a relatively wide spectrum of relaxation times. We have calculated best approximations of this spectrum by deconvoluting the mechanical after-effect curves. The resulting distribution is symmetrical in logarithm of the relaxation time with a width at half-height which is a factor of 20 in relaxation time. The significance of these findings is discussed in terms of our understanding of oxygen mobility in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}}. 16 refs., 5 figs.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5329239
• Report Number(s): LA-UR-91-2736; CONF-9109213--1; ON: DE91018043
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
DIFFUSION
ELEMENTS
FRICTION
HIGH-TC SUPERCONDUCTORS
INTERNAL FRICTION
NONMETALS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES