Microwave low-field absorption and ESR in Kx(C60)1-y(C70)y and KxC70

A. A. Zakhidov, K. Imaeda, A. Ugawa, K. Yakushi, H. Inokuchi, Z. Iqbal, R. H. Baughman, B. I. Ramakrishna, Y. Achiba

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Superconductivity (SC) in K-doped molecular alloys of C60 and C70 are studied by means of the nonresonant microwave low-field signal (LFS) and conventional ESR, and a LFS-search for SC in KxC70 is performed. The critical temperature of Kx(C60/C70) determined at the onset of hysteretic LFS, decreases to Tc=16K (at about 10% C70), and Tc=10K (at about 25% C70), compared with Tc=19K in pure KxC60 suggesting the decrease of electron-phonon coupling. A strong multicomponent g=2 ESR signal appears and coexists with LFS at low T for SC composition of Kx(C60/C70) indicating presence of a non-SC metallic phase. At overdoping LFS disappears and a single ESR line is enormously broadened to Δ Hpp(300K) = 80G. In KxC70 doped under the same conditions the LFS is not detected, indicating absence of SC above 5K, while a narrow ESR single line appears.

Original languageEnglish (US)
Pages (from-to)411-412
Number of pages2
JournalPhysica C: Superconductivity and its applications
Issue numberPART 1
StatePublished - Dec 1 1991


ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

Cite this

Zakhidov, A. A., Imaeda, K., Ugawa, A., Yakushi, K., Inokuchi, H., Iqbal, Z., Baughman, R. H., Ramakrishna, B. I., & Achiba, Y. (1991). Microwave low-field absorption and ESR in Kx(C60)1-y(C70)y and KxC70. Physica C: Superconductivity and its applications, 185-189(PART 1), 411-412. https://doi.org/10.1016/0921-4534(91)92008-Y