Thin YBCO films on (001) substrates grown by injection MOCVD

YBCO thin (about ) films were deposited at on (001) by single-source injection CVD. Precisely controlled microamounts of organometallic -diketonates dissolved in an organic solvent were injected sequentially into the evaporator by means of a computer-driven injector and the resultant vapour was transported into the deposition zone. The influence of the vapour phase composition on films' properties was investigated. A mixture of and -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 in-plane orientation with respect to substrate axes was found. Bidirectional twinning was established in the crystallites of both types. of the films (about 90 K) was almost independent of the vapour phase composition in the studied range. However, the critical current density depended clearly on the vapour phase composition in relation to the ratio variation. of the films varied in the range .