Two-dimensional behavior in (YBa 2Cu 3O 7− δ) 24/(PrBa 2Cu 3O 7− δ) 2 multilayer thin films

Abstract

We have measured the field and angular dependencies of the resistive broadening of epitaxial (YBa 2Cu 3O 7− δ ) 24/(PrBa 2Cu 3O 7− δ ) 2 multilayer thin film. The results show that in low measuring current density regime, the resistive broadening induced by magnetic field depends mainly on the orientation of applied magnetic field with respect to the c-axis rather than the macroscopic Lorentz force. The field dependence of the activation energy for H‖ c follows a logarithmic law, U∝ln H, similar to the results reported by Brunner et al. [O. Brunner, L. Antognazza, J.-M. Triscone, et al., Phys. Rev. Lett. 67 (1991) 1354.], suggesting a 2D character in the multilayer thin film. The angular dependence of the activation energy U and the characteristic temperature T* can be scaled by 2D model proposed by Kes et al. [P.H. Kes, J. Aarts, V.M. Vinokur, et al., Phys. Rev. Lett. 64 (1990) 267]. The phenomenon may be attributed to the flux lines that are cut by the insulating PrBCO layers when the applied magnetic field is tilted away from the ab-plane.