Thermal and disorder fluctuations in anisotropic superconducting Nd1.85Ce0.15CuO4-x epitaxial films

The anisotropic vortex transport properties of c-axis-oriented Nd1.85Ce0.15CuO4-x superconducting epitaxial films are found consistent with a dislocation-mediated second-order vortex-solid melting transition. The anisotropic critical exponents and the electronic mass ratio are determined from the scaling of the current-voltage characteristics. The nucleation energy of vortex dislocations due to both thermal and disorder fluctuations and its relation to the vortex elastic moduli is inferred from our experiments. © 1992 The American Physical Society.