Phys. Rev. Lett. 72, 3092-3095 (1994)

[Issue 19 - May 1994 ]

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Temperature dependence of the magnetic field penetration depth in Rb3C60 measured by ac susceptibility

A. M. Neminsky, P. N. Nikolaev, and D. V. Shovkun
Institute of Solid State Physics, 142432 Chernogolovka, Moscow district, Russia
E. E. Laukhina and E. B. Yagubskii
Institute of Chemical Physics, 142432 Chernogolovka, Moscow district, Russia
Received 5 August 1993

The temperature dependence of the magnetic field penetration depth lambda (T) is determined down to 0.2Tc by the ac-susceptibility measurements on the Rb3C60 fine powder with small, about 1 K, variation in the grains' superconducting transition temperatures. The lambda (T) temperature dependence is exponential at low temperatures, which allows us to determine the energy gap Delta 0=1.7kBTc. Deviations of the experimental dependence lambda (T) from BCS are small and can be explained by strong-coupling theory.

1994 The American Physical Society

PACS: 74.25.Ha, 74.70.Wz