Characteristics of High-$J_{c}$ GdBCO Coated Conductors Fabricated by the RCE-DR Process

We report the characteristics of GdBa
₂
Cu
₃
O
_7-δ
(GdBCO) coated conductors (CCs) on LaMnO
₃
(LMO)-buffered IBAD MgO template, produced by the Reactive Co-Evaporation Deposition & Reaction (RCE-DR) process. The transport and magnetic critical current density (
J
_c
) values of GdBCO CC samples were 3.7 and 2.92 MA/cm
²
at 77 K in self-field for
B
//
c
, respectively. Analyses by transmission electron microscopy revealed that a large amount of elongated round Gd
₂
O
₃
particles with 70-150 nm size and a small amount of the Cu-O phase were trapped in the GdBCO matrix, and a thick layer of the Cu-O phase was also found on the top surface of the GdBCO film, suggesting that the GdBCO film must be grown by the peritectic recombination reaction between Gd
₂
O
₃
and a liquid phase. While both the GdBCO film and some Gd
₂
O
₃
particles grown on the LMO-buffer layer were biaxially textured, the Gd
₂
O
₃
particles fully trapped in the GdBCO matrix were randomly oriented. The GdBCO film by RCE-DR possessed slightly degraded value of exponent α ~ 0.84 in the power-law relationship
J
_c
~
H
^-
a
and rather large anisotropy in field-orientation dependence of
J
_c
,
J
_c
(θ), and thus refinement of Gd
₂
O
₃
particles may be required for stronger flux pinning.