Control of the 2D/3D transition of the growth mechanism in the YBCO/Ce1−xLaxO2−x/2/SrTiO3 system
1998; Elsevier BV; Volume: 302; Issue: 2-3 Linguagem: Inglês
10.1016/s0921-4534(98)00203-2
ISSN1873-2143
AutoresD. Chambonnet, D. Keller, C. Belouet,
Tópico(s)Advanced Condensed Matter Physics
ResumoYba2Cu3O7−δ thin films have been deposited by pulsed laser-assisted deposition (PLD) on (001) SrTiO3 substrates coated by a lattice-matching buffer layer. The buffer layer, deposited by PLD prior to the YBCO film, consisted of a graded La-doped CeO2 layer, having the composition Ce(1−x)LaxO2−x/2, the La content x being decreased from 0.3 (substrate side) to 0.15 (YBCO film side) in order to achieve lattice matching at the substrate and at the film sides, respectively. It was found that this system permitted the growth of YBCO films with large-sized grains, by a quasi layer-by-layer mechanism up to thickness values in excess of 150 nm. The outcome of this preliminary study suggests that the achievement of high quality YBCO films aimed at microwave devices—smooth and having grains strongly coupled by Josephson coupling—entirely grown by a quasi layer-by-layer mechanism, may be within reach. The stake of this study is in the possible application of the lattice-matching concept to cost effective systems such as YBCO/MgO or YBCO/Al2O3.
Referência(s)