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Superconductivity of κ-(BEDT–TTF)2 Cu[N(CN) 2]Br: Isotope Effect Revisited

Published online by Cambridge University Press:  10 February 2011

M. Tokumoto ,
N. Kinoshita ,
Y. Tanaka  and
H. Anzai
M. Tokumoto
Affiliation:
Electrotechnical Laboratory, Tsukuba, Ibaraki 305, Japan, [email protected]
N. Kinoshita
Affiliation:
Electrotechnical Laboratory, Tsukuba, Ibaraki 305, Japan, [email protected]
Y. Tanaka
Affiliation:
Electrotechnical Laboratory, Tsukuba, Ibaraki 305, Japan, [email protected]
H. Anzai
Affiliation:
Himeji Institute of Technology, Kamigori, Hyogo 678–12, Japan
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Abstract

In 1991, we reported a normal isotope effect in organic superconductor κ-(BEDT–TTF)2Cu[N(CN)2]Br, when all the hydrogen atoms of BEDT – TTF were replaced with deuterium. In other words, Tc was depressed by as much as 0.9 K, in contrast to the “inverse isotope effect” commonly observed in 10K-class organic superconductors. Recently, it was reported that the deuterated κ-(BEDT–TTF)2Cu[N(CN)2]Br shows an insulating nature when cooled very rapidly. Therefore, it is necessary for us to reexamine the superconducting transition of both deuterated and undeuterated κ- (BEDT – TTF)2Cu[N(CN)2]Br by SQUID measurements with special attention to the cooling speed. We studied the effect of cooling rate ranging from 10 K/min down to as slow as 0.02 K/min, and observed a significant effect not only on the superconducting transition temperature Tc but also on the superconducting volume fraction.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 488: Symposium J – Electrical, Optical & Magnetic Properties of Organic IV , 1997 , 903
Copyright
Copyright © Materials Research Society 1998

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References

1. Kini, A. M., Geiser, U., Wang, H. H., Carlson, K. D., Williams, J. M., Kwok, W. K., Vandervoort, K. G., Thompson, J. E., Stupka, D. L., Jung, D. and Wangbo, M.-H., Inorg. Chem. 29, 2555 (1990)Google Scholar
2. Tokumoto, M., Kinoshita, N., Tanaka, Y. and Anzai, H., J. Phys. Soc. Jpn. 60, 1426 (1991)Google Scholar
3. Oshima, K., Urayama, H., Yamochi, H. and Saito, G., Synth. Metals 27, A473 (1988)Google Scholar
4. Wang, H. H., Carlson, K. D., Geiser, U., Kini, A. M., Schultz, A. J., Williams, J. M., Montgomery, L. K., Kwok, W. K., Welp, U., Vandervoort, K. G., Boryschuk, S. J., Crouchi, A. V. Strieby, Kommers, J. M. and Watkins, D. M., Synth. Metals 41–43, 1983 (1991)Google Scholar
5. Ito, H., Watanabe, M., Nogami, Y., Ishiguro, T., Komatsu, T., Saito, G. and Hosoito, N., J. Phys. Soc. Jpn. 60, 3230 (1991)Google Scholar
6. Komatsu, T., Matsuoka, N., Nakamura, T., Yamochi, H., Saito, G., Ito, H. and Ishiguro, T., Phosphorus, Sulfur, and Silicon 67, 295 (1992)Google Scholar
7. Tokumoto, M., Murata, K., Kinoshita, N., Yamaji, K., Anzai, H., Tanaka, Y., Hayakawa, Y., Nagasaka, K. and Sugawara, Y., Mol. Cryst. Liq. Cryst. 181, 285 (1990)Google Scholar
8. Saito, G., Otsuka, A. and Zakhidov, A. A., Mol. Cryst. Liq. Cryst. 284, 3 (1996)10.1080/10587259608037906Google Scholar
9. Nakazawa, Y. and Kanoda, K., Phys. Rev. B 53, R8875 (1996)10.1103/PhysRevB.53.R8875Google Scholar
10. Kwok, W. K., Welp, U., Carlson, K. D., Crabtree, G. W., Vandervoort, K. G., Wang, H. H., Kini, A. M., Williams, J. M., Stupka, D. L., Montgomery, L. K. and Thompson, J. E., Phys. Rev. B 42, 8686 (1990)Google Scholar
11. Kawamoto, A., Miyagawa, K. and Kanoda, K., Phys. Rev. B 55, 14140 (1997)Google Scholar
12. Kund, M., Müller, H., Biberacher, W., Andres, K. and Saito, G., Physica B 191, 274 (1993)Google Scholar