Effects of excimer-laser irradiation of LaAlO3(100) single crystals: Influence on superconducting YBa2Cu3O7-x film growth

3 (100) single crystal substrates have been investigated. Poorly absorbed KrF irradiation leads to localized, deep, and unstable damage on the crystal surfaces. By contrast ArF has been found to induce well-localized roughness and microcracks on LaAlO₃(100) surfaces at fluences between 0.2 and 1.8 J/cm². The material emission threshold was estimated at around 0.5 J/cm² and cracks appeared above 1.4 J/cm². The substrate surface state determines YBa₂Cu₃O_7-x film growth, leading to morphological changes that have been related to a decrease in adatom mobility on the substrate. The most striking feature is the drastic reduction in YBa₂Cu₃O_7-x outgrowth density inside the irradiated areas. Irradiation has little effect on film crystalline properties. The main effect on the electrical properties can be restricted to a decrease of critical current density up to a factor of 10⁴, but such an important decrease is only observed in the most intensively irradiated substrates. Received: 18 November 1996/Accepted: 12 June 1997