Local approximation oscillatory differential method for the analysis of physical processes at the interface between vortex and Meissner regions in superconductors

A “differential” method for local diagnostics of superconductors has been developed. Regular steps with identical heights through certain intervals of an external field have been revealed on the magnetic-field dependences of the trapped magnetic flux density $B_{\text{tr}}(H_{0})$ and the effective demagnetizing factor $n_{\text{eff}}(H_0)$ of bulk and film YBCO samples. It has been shown that the sample in high magnetic fields “decays” stepwise into subcrystallites and nanocrystallites whose size is much smaller than the depth of penetration of the magnetic field $\lambda$.