Relation between Pinning Potential and Critial Current Density of YBaCuO Superconducting Thin Films

The relation between the pinning potential and the critical current density of YBaCuO thin films in weak magnetic fields is studied experimentally. The pinning potential U is obtained by comparing the current-voltage characteristics of the film with the flux-creep theory. The values U=25–120 meV are obtained for films with the critical current density j_c(T=0)=5.3×10⁵–1.8×10⁷ A/cm². It is shown that the pinning potential increases with the increase of the critical current density. The obtained results can be qualitatively explained with the pinning model of isolated vortices.