Superconducting Magnetization above the Irreversibility Line in   Tl2Ba2CuO6
  Piezolever torque magnetometry has been used to measure the magnetization of superconducting Tl2Ba2CuO6. Three crystals with different levels of oxygen overdoping were investigated in magnetic fields up to 10 Tesla. In all cases, the magnetization above the irreversibility line was found to depart from the behaviour M ~ ln(Hc2/H) of a simple London-like vortex liquid. In particular, for a strongly overdoped (Tc = 15K) crystal, the remnant superconducting order above the irreversibility line is characterized by a linear diamagnetic response (M ~ H) that persists well above Tc and also up to the highest field employed. 
C. Bergemann, A. W. Tyler, A. P. Mackenzie, J. R. Cooper, S. R. Julian   and D. E. Farrell