In-plane lattice constant relaxation during laser ablation of YBCO and yttria-stabilized zirconia

Abstract

In situ reflection high energy electron diffraction (RHEED) studies were performed during the growth of YBa 2Cu 3O 7− x (YBCO) on (100)SrTiO 3, (100)MgO and of yttria-stabilized zirconia (YSZ) on native oxide on (100)Si by laser ablation. Line-scans through the RHEED patterns were taken automatically at time intervals of 100 ms; thus the in-plane lattice constant and evolution of the crystalline quality could be measured in real time. On SrTiO 3 the lattice constant of YBCO was relaxed to its bulk value within 1 nm, whereas on MgO the relaxation was finished after 8 nm deposition of YBCO. YSZ grows expitaxially on the native oxide on (100)Si. During the initial stages of growth, the RHEED pattern became totally diffuse, but then a streaky diffraction pattern developed indicating an increase in crystalline quality of the YSZ with increasing film thickness. The energy dependence of the dechanneling parameter of the ion-channeling indicates that most of the defects of the YSZ film are dislocations with an increasing density toward the YSZ-Si interface.