Enhancement of In-Field Critical Current Density of BaZrO3-Added (Y, Gd) BCO-Coated Conductors by Using a Multi-Coating TFA-MOD Method

We have investigated the in-field critical current properties in BaZrO
₃
-added (Y, Gd) Ba
₂
Cu
₃
O
_7-δ
(YGdBCO)-coated conductor fabricated by using a multi-coating trifluoroacetates metal-organic deposition (MOD) method. We compared these properties with EuBCO-coated conductor fabricated by the pulsed laser deposition (PLD) method. The sample using the 30-nm once-coat-layer-thickness d
_once
shows superior in-field J
_c
down to 4.2 K than that of the previous standard coating using 170-nm-thick layer for each coating. From the analysis of E-J characteristics, an analytical expression for J
_c
as a function T and B has been derived. It was confirmed that the high J
_c
region in sample with d
_once
= 30 nm is widely spread in high-temperature and high-magnetic-field region. By comparison with the J
_c
properties of the BaHfO
₃
-added PLD CCs, the minimum J
_c
, which is estimated from magnetic field angle dependence, shows even higher value up to 5 T of magnetic field at 65 K and up to 3 T at 77 K. From these results, the new MOD-YGdBCO process using the thin once-coat-layer-thickness is very promising for the practically important mid field region such as 3 to 5 T.