Hostname: page-component-8448b6f56d-dnltx Total loading time: 0 Render date: 2024-04-18T17:51:23.257Z Has data issue: false hasContentIssue false

Preparation and Properties of Organic Superconductor κ-(Bedt-TTF)2 [Cu(NCS)2] and Its Related Materials

Published online by Cambridge University Press:  25 February 2011

Gunzi Saito*
Affiliation:
Department of Chemistry, Faculty of Science, Kyoto University, Sakyo-ku, Kitashirakawa, Oiwake, Kyoto 606, Japan
Get access

Abstract

κ-(BEDT-TTF)2 [Cu(NCS)2] has a two-dimensional (2D) layered structure. The compound is metallic with the room temperature conductivity of 10–40 S/cm within the 2D plane but showed a semiconductive-like anomaly between 270 and 90K. The superconducting transition was observed at Tc=10.4K and Tc increased by 10% on the sample of deuterated BEDT-TTF (Tc=11.4K). The upper critical field, Hc2, was more than 20 Tesla below 2K within the 2D plane which is more than the expected value from the simple BCS theory. The transport critical current density was estimated as 100 A/cm2 (5.1K, 0 Tesla, l//b, H//c) which is an order of magnitude smaller than that obtained from the magnetization curve hysteresis. 1H-NMR showed a big enhancement of the relaxation rate well below Tc. The tunneling spectra showed anisotropic gap and the magnetic field penetration depth measurements strongly suggest that this system is a gapless superconductor. (BEDT-TTF)2[KHg(SCN)4] is an organic metal and showed both Shubnikov-de Haas effect and angle-dependent quantum oscillation indicating that this system has a warped 2D Fermi surface.

Type
Research Article
Copyright
Copyright © Materials Research Society 1990

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Urayama, H., Yamochi, H., Saito, G., Nozawa, K., Sugano, T., Kinoshita, M., Sato, S., Oshima, K., Kawamoto, A., and Tanaka, J., Chem. Lett, 1988, 55.Google Scholar
2. Oshima, K., Urayama, H., Yamochi, H., and Saito, G., J. Phys. Soc. Jpn., 57, 730(1988).Google Scholar
3. Nozawa, K., Sugano, T., Urayama, H., Yamochi, H., Saito, G., and Kinoshita, K., Chem. Lett., 1988, 617.Google Scholar
4. For reviews, Saito, G., Urayama, H., Yamochi, H., and Oshima, K., Synth. Met., 21, A331(1988), in Advances in Superconductivity . edited by Kitazawa, K. and Ishiguro, T. (Springer-Verlag, 1989), p107,Google Scholar
Urayama, H., Yamochi, H., Saito, G., Sato, S., Sugano, T., Kinoshita, M., Kawamoto, A., Tanaka, J., Inabe, T., Mori, T., Maruyama, Y., Inokuchi, H., and Oshima, K., Syn. Met., 27, A393(1988);Google Scholar
Saito, G. and Urayama, H., in The Science of Superconductivity and New Materials, edited by Nakajima, S. (World Scientific Pub., 1989), p60;Google Scholar
Saito, G., in Lower-Dimensional Systems and Molecular Devices, edited by R.M.Metzger (Plenum Press, NATO-ASI Proceedings, to be published); Proceedings of the International Conference on M2S-HTSC, Stanford, 1989, to be published; Proceedings of Symposium New Developments in the Chemistry and Properties of Low-Dimensional and Conducting Solids, edited by J.M. Williams (Mol. Cryst. Liq. Cryst. to be published), see also papers in Proceedings of ICSM ’88, Syn. Met., 27 (1988) and Proceedings of ISSP-ISOS, The Physics and Chemistry of Organic Superconductors, edited by G.Saito and S.Kagoshima (Springer-Verlag, to be published).Google Scholar
5. Urayama, H., Yamochi, H., Saito, G., Sato, S., Kawamoto, A., Tanaka, J., Mori, T., Maruyama, Y., and Inokuchi, H., Chem. Lett., 1988, 463.Google Scholar
6. Oshima, M., Mori, H., Saito, G., and Oshima, K., ibid, 1989, 1159.Google Scholar
7. Urayama, H., Yamochi, H., Saito, G., Sugano, T., Kinoshita, M., Inabe, T., Mori, T., Maruyama, Y., and Inokuchi, H., ibid, 1988. 1057.Google Scholar
8. Ugawa, A., Ojima, G., Yakushi, K. and Kuroda, H., Phys. Rev. B 38, 5122(1988).Google Scholar
9. Oshima, K., Mori, T., Inokuchi, H., Urayama, H., Yamochi, H., and Saito, G., Syn. Met., 27, A165(1988).Google Scholar
10. Murata, K., Tokumoto, M., Anzai, H., Honda, Y., Kinoshita, N., Ishiguro, T., Toyota, N., Sasaki, T., and Muto, Y., ibid, A263(1988).Google Scholar
11. Mori, H., Tanaka, S., Yamochi, H., Saito, G., and Oshima, K., in The Physics and Chemistry of Organic Superconductors, edited by Saito, G. and Kagoshima, S. (Springer-Verlag, to be published).Google Scholar
12. Schirber, J.E. and Northrup, C.J.M. Jr., Phys. Rev. B 10, 3818(1974).Google Scholar
13. Oshima, K., Urayama, H., Yamochi, H., and Saito, G., Physica C 154, 1148(1988).Google Scholar
14. Mori, H., Nakao, K., Hirabayashi, I., Tanaka, S., Oshima, K., and Saito, G., in Proceedings of 2nd International Symposium on Superconductivity (Springer-Verlag, to be published).Google Scholar
15. Oshima, K., Yu, R.C., Chaikin, P.M., Urayama, H., Yamochi, H., and Saito, G., in Ref. 11, to be published.Google Scholar
16. Tokumoto, M., Anzai, H., Takahashi, K., Murata, K., Kinoshita, N., and Ishiguro, T., Syn. Met., 27, A305(1988).Google Scholar
17. Iye, Y., in Studies of High Temperature Superconductors, edited by Narlikar, A.V. (NOVA Science Pub. Inc., 1989), p263.Google Scholar
18. Malozemoff, A.P., Worthington, T.K., Yeshurun, Y., and Holtzberg, F., Phys. Rev. B 38, 7203(1988).Google Scholar
19. Oshima, K., Mori, T., Urayama, H., Yamochi, H., and Saito, G., ibid, 37, 938(1988).Google Scholar
20. Oshima, K. (private communication).Google Scholar
21. Sugano, T., Hayashi, H., Kinoshita, M., and Nishikida, K., Phys. Rev. B 39, 11387(1989).Google Scholar
22. Sugano, T., Terui, K., Mino, S., Nozawa, K., Urayama, H., Yamochi, H., Saito, G., and Kinoshita, M., Chem. Lett., 1988, 1171.Google Scholar
23. Gartner, S., Gogu, E., Heinen, I., Keller, H.J., Klutz, T., and Schweitzer, D., Solid State Commun., 65, 131(1988).Google Scholar
24. Takahashi, T., Tokiwa, T., Kanoda, K., Urayama, H., Yamochi, H., and Saito, G., Physica c, 153–155, 487(1988);Google Scholar
Syn. Met., 27, A319(1988);Google Scholar
Takahashi, T., Kanoda, K., Sano, K., Watabe, M., Mori, H., and Saito, G., in Ref. 11, to be published.Google Scholar
25. Hasegawa, Y. and Fukuyama, H., J. Phys. Soc. Jpn., 56, 877(1987) .Google Scholar
26. Takigawa, M., Yasuoka, H., and Saito, G., ibid, 56, 873(1987).Google Scholar
27. Hasegawa, Y. and Fukuyama, H., ibid, 56, 2619(1987).Google Scholar
28. Maruyama, Y., Inabe, T., Urayama, H., Yamochi, H., and Saito, G., Solid State Commun., 67, 35(1988);Google Scholar
Maruyama, Y., Inabe, T., Mori, H., Yamochi, H., and Saito, G., in Ref. 11, to be published.Google Scholar
29. Kanoda, K., Takahashi, T., and Saito, G., in Proceedings of the International Conference on M2S-HTSC, Stanford, 1989, to be published;Google Scholar
Kanoda, K., Akiba, K., Takahashi, T., and Saito, G., in Ref. 11, to be published.Google Scholar
30. Osada, T., Yagi, R., Kagoshima, S., Miura, N., Oshima, M., and Saito, G., in Ref. 11, to be published.Google Scholar