Refining Process of BaZrO3 Particles in Coated Conductors by TFA-MOD Method

A wide range of coating thicknesses was utilized in the trifluoroacetate metal-organic decomposition process for (Y, Gd) Ba
₂
Cu
₃
O
_7-δ
(YGdBCO) coated conductor including BaZrO
₃
(BZO) particles with a thin once-coated thickness(donce), which was developed for improving the critical current density in a magnetic field (Jc(B)). The value of Jc (B) increased as donce decreased to 30 nm, and a sample fabricated with donce = 30 nm exhibited high values of Jc(B) of 0.27 and 1.60 MA/cm
²
at 77 and 65 K, respectively, at 3 T (B//c). However, the value of Jc( B) of a sample with donce = 17 nm was almost the same as or slightly lower than that of the sample with donce = 30 nm. This tendency was explained by the change in the size of the BZO particles in the YGdBCO superconducting films. Additionally, the Cu elemental peak and the valleys of other elements were observed at the same position and at certain intervals in the elemental concentration line profiles along the depth direction of the precursors, fabricated under different donce conditions from 170 to 30 nm. However, the peaks and valleys were extremely suppressed, and the wave structure was barely observed in the sample with donce = 17 nm. The refining of BZO particles by reducing donce could be explained by the limited diffusion due to the existence of the concentration valleys/peaks. Moreover, the effect of the diffusion barrier due to the valleys/peaks might become weaker in the sample with donce = 17 nm.