Abstract
Bulk superconducting samples of type GdBa
2
Cu
3−
x
Ru
x
O
7−
δ
phase, Gd-123, with
x
ranging from 0.0 to 0.15 were prepared by the conventional solid-state reaction technique. X-ray powder diffraction (XRD) and the electrical resistivity measurements were performed in order to investigate the effect of Ru
4+
ions substitution on Gd-123 phase. Enhancement of the phase formation and the superconducting transition temperature
T
c
for GdBa
2
Cu
3−
x
Ru
x
O
7−
δ
phase up to
x
=0.05 was observed. The effect of magnetic field up to 4.4 kG on the electrical resistivity behavior of the prepared samples was studied to investigate the flux motion of this phase. The derived flux pinning energy
U
, based on the thermally activated flux creep TAFC model, decreased with increasing the magnetic field
B
. The flux pinning energy followed the exponent behavior as
U
(
B
)∼
B
−
β
. The superconducting transition width
ΔT
increased as the magnetic field increased, showing the scaling relation as
ΔT
∼
B
n
. Using Ambegaokar and Halperin AH theory, the magnetic field and temperature dependence of
U
was found to be
U
(
B
,
T
)∼
ΔTB
−
η
,
η
=
β
+
n
. The critical current density
J
c
(0) enhanced up to
x
=0.05, beyond which it decreased with further increase in Ru-content.