Mechanism of Quenching of Superconductivity in the YBa2Cu3O7-Delta System on Substitution of Zn For Cu
Författare
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.
Avdelning/ar
Publiceringsår
2010
Språk
Engelska
Sidor
2135-2148
Publikation/Tidskrift/Serie
International Journal of Modern Physics B
Volym
24
Issue
14
Dokumenttyp
Artikel i tidskrift
Förlag
World Scientific Publishing
Ämne
- Physical Sciences
- Natural Sciences
Nyckelord
- magnetic pair-breaking
- local lattice distortion
- Zn-doping
- XAFS
- density of states
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 0217-9792