In-plane and out-of-plane dissipation in c -axis-oriented (Bi,Pb)2Sr2Ca2Cu3O x silver-sheathed tapes

The temperature dependence of the out-of-plane and in-plane resistance of a c-axis-oriented (Bi,Pb)2Sr2Ca2Cu3O x silver-sheathed tape with high critical current density (Jc>2×104 A/cm2, 77 K, 0 T) has been investigated under applied fields up to 0.9 T. It is found that the in-plane and the out-of-plane resistance transitions are quite different: (1) The out-of-plane zero resistance temperature is much higher than the in-plane one, i.e., Tcab(H)≪Tcc(H), and the difference increases with magnetic field; (2) the out-of-plane zero resistance temperature corresponds to the c-axis decoupling temperature. These phenomena are attributed to different dissipation mechanisms. The in-plane dissipation at low temperature results from the thermally activated flux–flow, while the out-of-plane dissipation originates from the Josephson junction dissipation of weakly coupled c-axis grain boundaries and/or intrinsic Josephson junctions.