PrBa2Cu3O7thickness dependence of current-voltage behaviors in YBa2Cu3O7/PrBa2Cu3O7multilayers

The current-voltage (I–V) characteristics were measured for YBa2Cu3O7(24Å)/PrBa2Cu3O7(12Å, 24Åand 96Å) (YBCO/PBCO) multilayers in the perpendicular magnetic fields H(H| c-axis) up to 10 T. From the analysis of the vortex-glass (VG) phase transition with a transition temperature Tgand a dynamical critical exponent z, it is found that the dynamics of vortex system is influenced by the thickness of PrBa2Cu3O7layers. For YBCO(24Å)/PBCO(12Å) (24/12) multilayers, the I–Vbehaviors can be almost explained by three-dimensional VG transition. While, for 24/12 multilayers the quasi-two-dimensional VG transition leads a reasonable value of z. In the high fields (H> 4T) the parameters Tgand zof 24/24 are similar to ones of 24/96 rather than ones of 24/12. While, they approach to ones of 24/12 when the values of Hare less than 1 T. This behavior is discussed with the current dependence of exponents α in power law (V∼ Iα).