Flux pinning characteristics and material power law of melt-textured YBa2Cu3O7-delta

Low-electric-field E-J curves of YBa2Cu3O7-delta were determined from 0.27 to 1.34 T at various temperatures from 52 to 83 K with the magnetic sweepin g method by VSM. Using an empirical material power law E = E-c(J/J(c))(n), we obtained the characteristic pinning potential U-0(T, H) and real critica l current density J(c)(T, H) by an appropriate definition of E-c. By furthe r investigation of the changing shape of the pinning potential well, we int erpreted the peak effect of U-0 with temperature in high temperature superc onductors (HTSCs).