Europhys. Lett.
Volume 76, Number 3, November 2006
Page(s) 443 - 449
Section Condensed matter: structural, mechanical and thermal properties
Published online 11 October 2006
Europhys. Lett., 76 (3), pp. 443-449 (2006)
DOI: 10.1209/epl/i2006-10300-9

Unravelling the role of Cu-O chain length on the superconducting properties of $\rm SmBa_2Cu_3O_{6+\delta}$ via Al doping and clustering

M. Scavini1, M. Daldosso1, 2, S. Cappelli1, C. Oliva1, M. Brunelli2, C. Ferrero2 and A. Lascialfari3, 4

1  Dipartimento di Chimica Fisica ed Elettrochimica dell'Universita di Milano I-20133 Milano, Italy
2  European Synchrotron Radiation Facility - av. J. Horowitz, BP 220 F-38043 Grenoble Cedex, France
3  Istituto di Fisiologia Generale e Chimica Biologica, Università di Milano Milano, Italy
4  CNR-INFM, c/o Dipartimento di Fisica "A. Volta", Università di Pavia I-27100 Pavia, Italy

received 19 May 2006; accepted in final form 18 September 2006
published online 11 October 2006

The superconducting properties of the $\rm SmBa_2Cu_3O_{6+\delta}$ superconductor change dramatically upon oxidation. The driving force for these changes is still under debate because many concomitant structural changes occur. In order to highlight the specific role of Cu-O chain ordering on the rise of superconductivity in this system, Al-doped $\rm SmBa_2Cu_3O_{6+\delta}$ samples have been examined, having equal aluminium and oxygen concentration and nearly the same structure but different mean length of Cu-O chain fragments. For the first time, it is clearly shown that, keeping all the other structural properties unchanged, the local increase of the chain length determines a significant enhancement of the superconducting properties, i.e. TC and Meissner fraction.

61.10.Nz - X-ray diffraction.
74.62.Dh - Effect of crystal defects, doping and substitution.
74.72.Bk - Y-based cuprates.

© EDP Sciences 2006