SCALING OF THE FLUX-PINNING FORCE IN EPITAXIAL BI2SR2CA2CU3OX THIN-FILMS

Magnetic-field and temperature dependence of the critical current density J(c) is investigated in epitaxial Bi2Sr2Ca2Cu3Ox thin films. For the magnetic field H applied parallel to the c axis, the flux pinning force density F(p) (=J(c)B) exhibits clear scaling behavior when H is normalized by the irreversibility field H*. The maximum pinning force density scales linearly with H*. This is the first observed scaling of F(p) in high-quality thin films of Bi oxides, which we can reasonably explain with flux-creep theory by assuming that the activation energy is proportional to the flux line spacing.