Ab-plane restrained flux motion of (110) (formula presented) thin-film superconductors

We have studied thermally activated flux movements in between the ab planes of (Formula presented) (110)-oriented films. The activation energy was found to scale as (Formula presented) with (Formula presented) and (Formula presented) which is different from previous reports on the c-oriented thin films or single crystals, with (Formula presented) and (Formula presented) where k is a constant and (Formula presented) is a threshold current density. This behavior implies that for films with c axis in-plane aligned to the substrate surface, flux movements are confined in between the ab planes. Such movements are opposed by an energy barrier generally higher than that for in-plane gliding, but lower than that of a cross-plane movement. At low field and current density, the flux dynamics is mostly three-dimensional (3D)-like. At high field and current density, however, the tendency of a 3D to 2D transition was observed.