Abstract
We have measured the transport critical current densities () of various bulk polycrystalline R-type high-temperature superconductors (R=Gd,Dy,Sm,Ho,Y) at 77 K as a function of magnetic field. The substitution of yttrium with magnetic rare-earth elements resulted in no appreciable improvement or deterioration in the transport values (typically in the range 200–600 A/ at H=0). The similar values of all five barium cuprate compounds and their rapid deterioration in weak magnetic fields in a similar manner (<10 A/ at H=1000 gauss) suggest the possibility of generic ‘‘weak link’’ problems in these compounds.
- Received 26 October 1987
DOI:https://doi.org/10.1103/PhysRevB.37.5828
©1988 American Physical Society