LaSrGaO4 substrate gives oriented crystalline YBa2Cu3O7−y films

As‐grown YBa2Cu3O7−y (YBCO) thin films of 70 nm thickness have been prepared on LaSrGaO4(001), (100), and (110) single‐crystal substrates at 700 °C using ArF laser ablation deposition. The c‐axis oriented thin films with smooth surface morphology are obtained on LaSrGaO4 (001) and (100) substrates. The zero resistance temperatures (Tc) of the films on the (001) and (100) substrates are 90.0 K, and 88.1 K, respectively. On the (110) substrate, (110) YBCO planes grow epitaxially. The resistance perpendicular to the c axis in this film is 1/3 of that parallel to the c axis, showing Tc⊥=85.9 K and Tc∥=84.4 K, respectively. These results suggest that a LaSrGaO4 substrate having a low dielectric constant is an excellent substrate for the epitaxial growth and device application of high‐Tc YBa2Cu3O7−y superconducting films.