Why does Ni suppress superconductivity in La1.85Sr0.15Cu1−yNiyO4?

Author

• Daniel Haskel
• Edward A. Stern
• V. Polinger
• Fatih Dogan, Missouri University of Science and TechnologyFollow

Abstract

The role played by Ni impurities in destroying the superconducting state of La_2-xSr_xCuO₄ is still unclear. This is partly due to the lack of clear experimental evidence on the effect of Ni substitution upon the atomic and electronic structure of this cuprate. To provide this information, we performed Ni /(-edge polarized XAFS measure-ments on oriented powder. A special magnetic alignment geometry allowed us to measure pure ~ and aAb-polarized XAFS in identical experimental conditions. We found that the NiO6 octahedra are contracted along the t-axis by 0.16(A) relative to the CuO₆ octahedra in Lal.~sSro.~sCuO4, dragging La atoms and causing the observed macroscopic t-axis contraction. This contraction reflects the non-Jahn-Teller 3d a state of Ni in this compound (similar to that in La2NiO₄) and indicates that Ni does not "trap" hole carders but rather, probably, "repels "them. We suggest that this repulsion is the mechanism behind T~suppression.

Recommended Citation

D. Haskel et al., "Why does Ni suppress superconductivity in La1.85Sr0.15Cu1−yNiyO4?," Synchrotron Radiation, vol. 6, no. 3, pp. 758 - 760, International Union of Crystallography, May 1999.

The definitive version is available at https://doi.org/10.1107/S090904959900148X

Department(s)

Materials Science and Engineering

Comments

Acknowledgements: We thank E Perez and M. Suenaga for their valuable help and A. Moodenbaugh for the Tc measurements. Research done under auspices of DOE Grant No. DE-FG03-98ER45681.

Keywords and Phrases

Superconductivity; Nickel doping; Jahn-Teller

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2026 International Union of Crystallography, All rights reserved

Publication Date

1999-05-01