Mechanism of Quenching of Superconductivity in the YBa2Cu3O7-Delta System on Substitution of Zn For Cu
Author
Summary, in English
Substituting Zn for Cu is known to rapidly quench superconductivity in the doped perovskites but the mechanism behind it is still not clearly understood. Single phase YBa2(Cu1-xZnx)(3)O7-delta (x=0.0 to 0.06) samples were synthesized and characterized using XRD, wet titration, resistivity, and ac susceptibility. Angle-integrated Valence Band Photo emission and Zn K-edge XAFS results clearly show that their oxygen stoichiometry (delta) changes on Zn substitution, there by adversely affecting the density of free charge carriers and hence the normal state resistivity and the T-c. However, the observed changes in the two happen to be too large to be accounted for solely on the basis of changes in the oxygen stoichiometry delta. We find that the Zn cation acts as a strong "impurity" scattering centre in the YBCO lattice and causes local lattice distortion (LLD). It consequently induces local magnetic moment, seen in our dc susceptibility measurements. It is thus a composite of (Delta delta), LLD and possibly also magnetic pair-breaking that is responsible for the rapid quenching of the super conductivity observed with Zn doping in this system.
Department/s
Publishing year
2010
Language
English
Pages
2135-2148
Publication/Series
International Journal of Modern Physics B
Volume
24
Issue
14
Document type
Journal article
Publisher
World Scientific Publishing
Topic
- Physical Sciences
- Natural Sciences
Keywords
- magnetic pair-breaking
- local lattice distortion
- Zn-doping
- XAFS
- density of states
Status
Published
ISBN/ISSN/Other
- ISSN: 0217-9792