Epitaxial growth of YBa₂Cu₃O_7-δ thin films on LiNbO₃ substrates

In situ epitaxial growth of YBa2Cu3O 7-δ thin films on Y-cut LiNbO3 substrates using a standard laser ablation technique is reported. Resistance of the films shows a normal metallic behavior and a very sharp (<1 K) superconducting transition with Tc(R=0) of 92 K. High critical current density of J c(77 K)=2×105 A/cm2 is observed, which is in accordance with epitaxial growth. Film orientation observed from x-ray diffraction spectra indicates that the c axis is normal to the substrate plane and the a axis is at 45°to the [11.0] direction of the hexagonal lattice of the substrate with two domains in mirror image to the (110) plane.