Magnetization measurements in field on a Bi2Sr2CaCu2O8 single crystal do not reveal any sharp phase transition between the normal and superconducting states. The M(H) curves for temperatures about Tc in fields up to 5 T all display diamagnetic behavior. Above the mean-field transition temperature TcMF, quasi-two-dimensional diamagnetic fluctuations are responsible. Below TcMF strong deviations from the conventional mean-field (Abrikosov) behavior lead to an apparent Tc(B) inadequacy of the mean-field theory to describe the vortex state below the crossover line Hc2(T).
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)