Double-sided YBa2Cu3O7-δ (YBCO) thin films were prepared on LaAlO3 substrates 50 mm in diameter by an off-axis pulsed laser deposition method. The surface of the YBCO films appeared to have low a boulder density with a surface roughness of about 3 nm. Spiral growth was observed at both sides of the thin films. X-ray diffraction data showed that the YBCO thin films had grown epitaxially on LaAlO3 with c-axis orientation and a full width at half maximum for the (005) rocking curve of 0.15°. The transition temperature was in the range of 86-88 K and the critical current density at 77 K was 2.4-3.7×106 A cm-2 at various positions on both sides of the film. The surface resistance of the YBCO films was estimated to be as low as ~1.0 mΩ at 19.57 GHz and 77 K on both sides of the YBCO films, which corresponds to a value of ~250 µΩ at 10 GHz and 77 K.

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