Specific heat (1-330K), magnetic susceptibility and Meissner effect of TlBaCaCuO samples

The superconductors Tl2Ba2CuO6+x, Tl2Ba2CaCu2O8+x and Tl2Ba2Ca2Cu3O10+x are characterized by X-ray diffraction, resistance, a.c. susceptibility, Meissner effect, normal-state susceptibility and specific heat measurements. Questions such as the homogeneity of the superconducting system, the order of the transition at Tc, the presence of a linear term γ* in the low temperature specific heat and the density of states at the Fermi level are addressed. © 1989.