Dissipation anisotropy of highly c-axis-oriented (Bi,Pb)(2)Sr2Ca2Cu3Ox silver sheathed tapes

Dissipation anisotropy of a highly c-axis-oriented (Bi,Pb)(2)Sr2Ca2Cu3Ox, silver-sheathed tape in the vicinity of T-c(T/T-c>0.9) has been investigated by measuring the dependence of the magnetoresistance on the applied field, the temperature and the angle (theta) between the magnetic field direction and the tape surface. The results show that the dissipation anisotropy increases with the increase of the field and the temperature. It is found that the dissipation is only related to the magnetic field component perpendicular to the tape surface (c-axis component), i.e., R(H,theta)=R(H sin theta). The experimental results can be accounted for in terms of the easy motion of two-dimensional (2D) pancake vortices along the CuO2 planes. (C) 1997 American Institute of Physics.