Mixed state properties of superconducting RbCs2C60

The temperature dependence of the upper critical magnetic field H-c2 of superconducting RbCs2C60 was determined. The value of H-c2(0) at zero temperature is estimated to be 87.6 T and the coherence length xi(0) = 1.9 nm. The lower critical field H, was studied using the ''trapped magnetic moment'' method. The value of H-c1(0) is estimated to be 1.6 mT and the penetration depth is lambda(0) = 720 nm. The corresponding Ginzburg-Landau parameter is kappa = 371. The temperature dependence of the coherence length close to T-c is compared to the predictions of the Ginzburg-Landau BSC and two-fluid theories. The magnetic field and the temperature dependence of the critical current density were studied and the irreversibility line determined. Long term magnetic relaxation was measured in it wide range of temperatures and magnetic fields.