A. Abrutis et al., THIN YBCO FILMS ON NDGAO3(001) SUBSTRATES GROWN BY INJECTION MOCVD, Superconductor science and technology, 10(12), 1997, pp. 959-965
YBCO thin (about 0.2 mu m) films were deposited at 825 degrees C on Nd
GaO3 (001) by single-source injection CVD. Precisely controlled microa
mounts of organometallic beta-diketonates dissolved in an organic solv
ent were injected sequentially into the evaporator by means of a compu
ter-driven injector and the resultant vapour was transported into the
deposition zone. The influence of the vapour phase composition on film
s' properties was investigated. A mixture of a(perpendicular to)- and
c(perpendicular to)-oriented YBCO crystallites exists in all deposited
films and its ratio depends on the vapour phase composition. For both
a and c perpendicular crystallites only 45 degrees in-plane orientati
on with respect to substrate axes was found. Bidirectional twinning wa
s established in the crystallites of both types. T-c of the films (abo
ut 90 K) was almost independent of the vapour phase composition in the
studied range. However, the critical current density J(c) depended cl
early on the vapour phase composition in relation to the c(perpendicul
ar to):a(perpendicular to) ratio variation. J(c) of the films varied i
n the range (0.2-5.0) x 10(6) A cm(-2).