Search

In order to improve the surface quality of the pulsed laser deposited YBCO thin films an off-axis deposition geometiy is proposed. Using this new PLD geometry, YBCO thin films have been grown on SrTi03 substrates. These films were found to have a good surface morphology without droplets or other particulates, and good supelrconducting and structural properties. We have obtained Tc(R=0)=89 K, R(300)/R(100)=2.6, ΔT=1.5 K, Jc=2×106 A/cm2 (at 77 K and zero magnetic field), and the FWHM of the rocking curve of (005) YBCO peak is about 0.12°. A study regairding the influence of the deposition parameters on the film quality is also presented.

The fabrication by sputtering of Nb/sub 0.75/Zr/sub 0.25/ thin films that showed critical temperature as high as 10.5 K is described. Transport critical current measurements on Nb/sub 0.75/Zr/sub 0.25/ films whose geometries were photolithographically defined in the micrometer range are reported. The measurements were performed as a function both of the temperature and of the magnetic field up to 6 T. The temperature behavior is compared with the Kim-Anderson model, and the magnetic field behavior of the resulting pinning force is compared with existing models. >

YBa/sub 2/Cu/sub 3/O/sub y/ epitaxial thin films have been grown on a PrBa/sub 2/Cu/sub 3/O/sub y/ layer deposited on a sapphire substrate, using XeCl excimer laser ablation for both depositions. The films were deposited in situ by means of a rotating multitarget system carrying the two targets. The substrate holder was heated by a CO/sub 2/ laser beam. The as-deposited films show a zero resistance critical temperature of 87 K and a high degree of epitaxiality with c-axis orientation. The samples have been patterned in the shape of strips of variable width between 10 mu m and 30 mu m. DC transport critical current densities for YBa/sub 2/Cu/sub 3/O/sub y/ grown on PrBa/sub 2/Cu/sub 3/O/sub y//Al/sub 2/O/sub 3/ have been measured as a function of the temperature and an applied magnetic field. >