Role of apical holes for superconductivity in π-type cuprates: NEXAFS results

Journal of Superconductivity and Novel Magnetism

Volumn 12, Issue 1, 1999, Pages 143-146

  Nucker, N ^a   Merz, M ^a   Schweiss, P ^a   Pellegrjn, E ^a   Schuppler, S ^a   Wolf, Th ^a   Chakarian, V ^b   Freeland, J ^b   Idzerda, Y U ^b   Klaser M ^c   Muller Vogt G ^c   Er, G ^d   Kikkawa, S ^d   Liu, G ^e  

^a KARLSRUHE INSTITUTE OF TECHNOLOGY   (Germany)

^b NAVAL RESEARCH LABORATORY   (United States)

^c UNIVERSITY OF KARLSRUHE   (Germany)

^d OSAKA UNIVERSITY   (Japan)

^e INSTITUTE OF PHYSICS   (China)

Author keywords

[No Author keywords available]

Indexed keywords

OXIDE SUPERCONDUCTORS; POLARIZATION; SINGLE CRYSTALS; X RAY SPECTROSCOPY;

APICAL HOLES; HIGH TEMPERATURE SUPERCONDUCTIVITY;

SUPERCONDUCTIVITY;

EID: 0343661306     PISSN: 15571939     EISSN: 15571947     Source Type: Journal    
DOI: None     Document Type: Article

References (22)

1. G. Bednorz and K. A. Müller, Z. Phys. B 64, 189 (1986).
2. J. Mustre de Leon et al., Phys. Rev. Lett. 65, 1675 (1990).
3. P. Schweiss et al., Phys. Rev. B 49, 1387 (1994).
4. Y. Ohta et al., Phys. Rev. B 43, 2968 (1991).
5. F. C. Zhang and T. M. Rice, Phys. Rev. B 37, 3759 (1987).
6. L. F. Feiner et al., Phys. Rev. Lett. 76, 4939 (1996).
7. J.B. Grant and A. K. McMahan, Phys. Rev. B 46, 8440 (1992).
8. E. Pellegrin et al., Phys. Rev. B 47, 3354 (1993).
9. M. Merz et al., Phys. Rev. Lett. 80, 5192 (1998).
10. Th. Wolf et al., J. Cryst. Growth 96, 1010 (1989);
11. A. Zibold et al., Physica C 171, 151 (1990).
12. Laboratoire Commun. CEA-CNRS.
13. J. Zaanen et al., Phys. Rev. Lett. 55, 418 (1985).
14. There is still some controversy in the literature on whether Cadoped but O-depleted samples of (Ca, Y)BCO are superconducting or not; two reports opposing each other can be found in Ref. 14. While we are not able to ultimately resolve this issue here, we tend to believe that the dispute seems to rest with polycrystalline vs. single crystalline samples and/or with annealing in inert gas vs. annealing in ultrahigh vacuum (UHV). We did observe superconductivity in Ca-substituted polycrystalline samples annealed in Ar flow, which is absent in UHV annealed single crystals independent of Ca content. The UHV annealed samples regained the usual bulk superconductivity below 78 K after oxygen annealing.
15. J. L. Tallon et al., Phys. Rev. B 51, 12911 (1995);
16. J. Hejtmanek et al., Phys. Rev. B 54, 16226 (1996).
17. G. C. Che et al., Physica C 270, 354 (1996).
18. G. Er et al., Physica C 181, 206 (1991).
19. See, e.g., T. Siegrist et al., Nature 334, 231 (1988);
20. Z. Hiroi et al., Nature 364, 315 (1993);
21. J. Karpinski et al., Physica C 234, 10 (1954).
22. N. Nucker et al. (unpublished).