Comparative Study Between Similarly Processed ${\rm YBa}_{2}{\rm Cu}_{3}{\rm O}_{7-{\rm x}}$ Films With ${\rm Y}_{2}{\rm BaCuO}_{5}$ or ${\rm BaSnO}_{3}$ Additions

A special YBa
₂
Cu
₃
O
_7-x
(YBCO) target with a thin sector of second phase material, in this case either Y
₂
BaCuO
₅
(Y211) or BaSnO
₃
(BSO), was used to deposit YBCO films with non-layered nanoparticles on single crystal LaAlO
₃
and biaxially textured Ni-5 at.% W substrates buffered with CeO
₂
and YSZ layers(coated conductors). Although identical processing conditions were used, TEM images indicated that random Y211 nanoparticles in the case of YBCO + Y211, and evenly spaced BSO nanocolumns in the case of YBCO+BSO, form in the YBCO films. While YBCO plane buckling was observed at many places in the case of YBCO + Y211, a high density of stacking faults and dislocations were observed in the case of YBCO+BSO near the BSO columns. In transport critical current density (
Jc
) angular dependence measurements, the absence of nanocolumns in YBCO + Y211 films resulted in the absence of a peak at 0deg ,
Jc
(
H
//
c
) , in
Jc
vs. thetas plots, as compared to a clear peak at 0deg observed in YBCO+BSO films with the nanocolumns. The in-field
Jc
measurements indicated small low-field
Jc
enhancements at 77 K in YBCO + Y211 films but more than an order of magnitude improvement in high-field
Jc
in YBCO + BSO films due to the differences in the microstructures.