Nernst effect in Tl-Ba-Ca-Cu-O high-${\mathit{T}}_{\mathit{c}}$ superconducting thin films

The dynamical behavior of magnetic flux in superconducting Tl-Ba-Ca-Cu-O films has been studied using the Nernst effect. Large temperature gradients of ∼${10}^5$ K/cm and, correspondingly, large thermal forces on flux lines were obtained by pulsed laser heating of films. Due to the large thermal driving forces it was possible to observe, at temperatures well below ${\mathit{T}}_{\mathit{c}}$, the transition from thermally assisted flux flow to flux creep and viscous flux flow.