The growth of ultrathin (1.7–7.3 nm) YBa 2 Cu 3 O 7− x films on the SrTiO 3 (100) substrate is investigated by the mean-energy ion scattering technique. It is found that the growth of islands proceeds according to the two-dimensional and three-dimensional models and depends on the growth conditions.

The growth of ultrathin (1.7-7.3 nm) YBa2Cu3O7-x films on the SrTiO3(100) substrate is investigated by the mean-energy ion scattering technique. It is found that the growth of islands proceeds according to the two-dimensional and three-dimensional models and depends on the growth conditions. (C) 2000 MAIK "Nauka/Interperiodica".

The evolution of YBa2Cu4O8 and CuO islands formed at the early stages of the deposition of Y-Ba-Cu-O layers is investigated. The average island size, island density, and island size distribution are determined as functions of deposition time. The evolution of both YBa2Cu3O7-x and CuO islands is shown to be controlled by the evaporation-condensation stage of mass transport. The laws are established which specify how the molecular flows of barium, copper, and yttrium oxides should vary to ensure growth of superconductor layers of the desired composition and structure.

The feasibility of producing high-quality films of the high-temperature superconducting material YBa 2 Cu 3 O 7-δ with thicknesses up to 2.6 µm by dc magnetron sputtering is demonstrated. It is found that inclusions consisting of CuO and YBa 2 Cu 3 O 8 coexist with the growing film and are “sinks” for defects, nonstoichiometric atoms, and mechanical stresses. X-ray diffraction and Rutherford backscattering studies show that the structural perfection of the films increases as the thickness is increased in the proposed production regime.

The possibility is demonstrated of preparing high-quality films of the high-temperature superconductor YBa2Cu3C7-δ with thicknesses up to 2.6 µm by dc magnetron sputtering. It is found that inclusions consisting of CuO and YBa2Cu3O8 coexist with the growing film and are “sinks” for defects, nonstoichiometric atoms, and mechanical stresses. Using x-ray diffraction and Rutherford backscattering, we find that the structural perfection of the films is improved by increasing the thickness when using the proposed fabrication technique.

A new model for the sputtering of multi-component materials is proposed, which allowed us to calculate the rate of selective sputtering of multi-component target and the transient time of selective sputtering. The model is based on the introduction of the new parameter : the threshold energy of selective sputtering. The model proposed and the analysis of experimental data on the ion etching rate of high temperature superconductors allowed us to evaluate the transient time of selective sputtering and sputtering rate for the case of YBCO target.

Superconducting YBa 2 Cu 3 O 7− x films were prepared by magnetron sputtering on Al 2 O 3 single crystals with a CeO 2 sublayer. Scattering of moderate-energy ions and x-ray diffraction were used to show that the films exhibit good single-crystal properties over the entire thickness up to 2.6 μ m. The hypothesis is advanced that the indentations formed by the growth of films above “extraneous” phase grains may act as defect sinks.

The results of the study of the growth of thick (up to 2.6 μm) YBCO films are presented. The content of a-oriented phase was observed to reduce with thickness as opposite to what was reported before. The orientation of c-phase is also improving with thickness as was shown by X-ray diffraction and Rutherford backscattering analysis. The electrical characteristics (critical current density and surface resistance at 77 K, 60 GHz) follow the same tendency. Two types of macrodefects were revealed by scanning electron microscopy: second-phase inclusions and holes. We suppose that these macrodefects can play the role of drains for defects and mechanical stress and thus stabilize the growth of the c-oriented phase and prevent the nucleation of the a-oriented phase.

High-temperature superconducting films up to 3.6 μ m thick were obtained and their properties requisite for the development of microwave devices were investigated. It is shown that YBa 2 Cu 3 O 7− δ films of thickness exceeding 3–5 λ L may be obtained for use in the microwave range.

The process of new-phase nucleation in the YBa 2 Cu 3 O 7− x system deposited by magnetron sputtering has been studied. The first experimental observation of the phenomenon of temporal self-organization in the course of new-phase formation, which was predicted theoretically, 1–3 is reported. Auto-oscillations in the number of nuclei of various chemical compounds 20–60 nm in size were observed to occur within the 15 to 300-s time interval, the total number of nuclei varying aperiodically from 10 13 m −2 to less than 10 11 m −2 .

A report is made on the results of experiments to prepare YBa 2 Cu 3 O 7− x films up to 2.6 μm thick on Al 2 O 3 /CeO 2 with good structural perfection and electrophysical parameters.