The measurement of the ac susceptibility of high-Tc superconductors submitted to a large temperature gradient provides information on the inhomogeneous and gradual nature of the superconducting-normal (S-N)and normal-superconducting (N-S) transitions. The variation of the gradient applied to the samples represents the essence of the thermometric mapping method (TMM). As a consequence, the borderline between the superconducting and normal states continuously sweeps the whole specimen, resulting in a huge broadening of the transition, and so its nonlinear fine structure can be observed. Since the details of the S-N or N-S transitions change due to the thermal cycling, its effect can be detected by the sensitive TMM. The experimental results reflect the deviations occurring in the behaviour of the samples and consequently in the properties of the gradual transition caused by the thermal cycles. In this way, the TMM is able to trace the effect of thermal cycling on the local superconducting properties of the materials.
ASJC Scopus subject areas
- Physics and Astronomy(all)