Substrate temperature dependence of the texture quality in YBCO thin films fabricated by on-axis pulsed-laser ablation

In applications of superconducting devices, the crystalline texture of high-quality YBa₂Cu₃O_7-x thin films is of primary importance. The preferred Mentation of the films can be essentially controlled by means of the substrate temperature, T_s. In order to study the dependence of the film texture on different T_s, a series of films were deposited on YSZ substrates by the on-axis pulsed-laser ablation technique. The substrate temperature was varied from 600°C to 800°C while the rest of the growth parameters remained the same. Various analytical techniques, including x-ray diffraction, scanning electron microscopy, micro-Raman spectroscopy and the four-point probe method, were applied to characterize the films At around T_s = 700°C, the best films with the smoothest surface morphology, lowest FWHM of the rocking curve and highest in-plane texture were obtained The resultant J_c in excess of 1 × 10⁶ A cm^-2 at 77 K and T_c around 91 K were also achieved at this temperature.