عنوان

On residual stress measurements in yttrium-based superconductor

Number

TLpq304480314

.Language of Text, Soundtrack etc

انگلیسی

Title Proper

On residual stress measurements in yttrium-based superconductor

General Material Designation

[Thesis]

First Statement of Responsibility

S. N. Alfaer

Name of Publisher, Distributor, etc.

King Fahd University of Petroleum and Minerals (Saudi Arabia)

Date of Publication, Distribution, etc.

1998

Specific Material Designation and Extent of Item

67

Dissertation or thesis details and type of degree

M.S.

Body granting the degree

King Fahd University of Petroleum and Minerals (Saudi Arabia)

Text preceding or following the note

1998

Text of Note

XRD and residual stress usd({\sim}\sin\sp2\psi)usd measurements were carried out on usd\rm YBa\sb2Cu\sb3O\sb{x}usd superconductor with varying oxygen stoichiometry usdx = 6.32usd to 7. Using published data for c-axis, T{c} and oxygen content it was found that the measured c-axis varies linearly with and is sensitive to variation of oxygen content and T{c}. Variation of a and b parameters with oxygen content revealed a transition from orthorhombic to tetragonal at 6.48. Orthorhombicity and volume of the unit cell were plotted against oxygen content and an unexpected volume contraction of the unit cell was observed. This was discussed in terms of energetically favored filling of oxygen sites. Slopes of the strain versus sin which is proportional to the residual stress, were plotted against oxygen content for certain reflections (006) and (115), for example. Different behaviors were observed and are attributed to a c-axis compressional stress increasing with oxygen content and an overall tensile residual stress in the ab-plane is also increasing oxygen content. Both effects reach saturation near fully oxygenated state usdx\ \approx\ 7.usd This explains the anomalous very small hydrostatic pressure effect on T{c} for fully oxygenated YBa2Cu3O{x} (usdx\ \approx\ 7)usd compared to a relatively high effect for oxygen deficient material. Similar results were observed for the oxygen disorder effect. Changes in T{c} for disordered material is attributed to changes in the residual stress induced by disorder phenomena.

Condensation

Pure sciences

yttrium barium copper oxide

S. N. Alfaer

Electronic name

p

[Thesis]

276903

a

Y