Bk. Roul, LOW-TEMPERATURE MAGNETIC AND MICROWAVE STUDIES OF GD0.95BA2CU3.05O7-DELTA-AGX COMPOSITES, Journal of superconductivity, 6(4), 1993, pp. 285-290
Gd0.95Ba2Cu3.05O7-delta: Ag(x) (x=0.0, 0.02, 0.04, 0.06) ceramic super
conducting samples were prepared by a co-precipation technique using o
rganic carbonates in the presence of stable polymers. The room-tempera
ture normal-state resistivity decreases with Ag addition. However, T(c
) and crystallographic parameters were uneffected. Low-temperature (4.
2 K) magnetic and electrical transport studies in high magnetic fields
(5 T) reveal that the addition of Ag into the Gd0.95Ba2Cu3.05O7-delta
(GBCO) enhances the magnetic critical current density (J(mc)), volume
pinning force (F(p)), flux explusion, and transport critical current
density (J(tc)). Microwave-induced dc voltage studies show the reducti
on in the total number of weak links between superconducting GBCO grai
ns with increase in Ag concentration. The flux creep rate was also inc
reased with increase in Ag concentration in GBCO resulting in stronger
pinning potential. The increase in J(mc), J(tc), and, hence, F(p) wit
h Ag addition in the GBCO suggests the creation of an SNS-type proximi
ty junction at the intergrannular region and stronger Josephson curren
t paths between the superconducting intergrains, which may be due to t
he physical densification and reduction of the total number of weak li
nks by Ag addition into the GBCO superconducting system.