The preparation of a YBa2Cu3O7−x/LaNiO3/YBa2Cu3O7−x sandwich structured film on a LaAlO3 (100) substrate by a sol-gel method was investigated. YBa2Cu3O7−x/LaNiO3/YBa2Cu3O7−x tri-layer heterostructures with different epitaxial characteristics can be deposited by controlling the heat treatment temperature. X-ray diffraction and transmission electron microscopy results show that the bottom YBCO fi...

We demonstrate a-axis YBa2Cu3O7−x/PrBa2Cu3O7−x/YBa2Cu3O7−x trilayers grown on (100) LaAlO3 substrates with improved interface smoothness. The are synthesized by ozone-assisted molecular-beam epitaxy. thickness of the PrBa2Cu3O7−x layer is held constant at 8 nm, and YBa2Cu3O7−x layers varied from 24 nm to 100 nm. X-ray diffraction measurements show all have >97% content. rms roughness thinnest t...

Nanostructuring of YBa2Cu3O7-x films is a challenging task on a way to the high-quality YBa2Cu3O7-x nanodevices because of the sensitivity of YBa2Cu3O7-x thin films to the patterning process. In this work we report on a "cold" nanopatterning procedure used for the structuring of the ultra-thin YBa2Cu3O7-x films by focused ion beam etching with a specially developed protection layer, which can b...

We probe the short-range pinning properties with the application of microwave currents at very high driving frequencies (47.7 GHz) on YBa2Cu3O7−δ films with and without sub-micrometer BaZrO3 inclusions. We explore the temperature and field ranges 60 K< T < Tc and 0< μ0H <0.8 T, with the field applied along the c-axis. The magnetic field induces a much smaller increase of the microwave resistivi...

2014 Previous ESR results from YBa2Cu3O7 powders are contradictory. We present results on YBa2Cu3O7 single crystals, obtained through systematic intensity measurements, a comparison of X and Q-band spectra, a comparison with the spectra from other related Y/Ba/Cu oxides, and a study of the influence of grinding the crystals. The ESR of conduction electrons was not detected. Although anisotropic...

We present measurements of the magnetic field dependent microwave surface resistance in laser-ablated YBa2Cu3O7−δ films on SrTiO3 substrates. BaZrO3 crystallites were included in the films using composite targets containing BaZrO3 inclusions with mean grain size smaller than 1 μm. X-ray diffraction showed single epitaxial relationship between BaZrO3 and YBa2Cu3O7−δ. The effective surface resist...

High intensity ultrasonic irradiation (sonication) of alkane slurries of polycrystalline YBa2Cu3O7−x leads to a significant modification of the grain morphology and, if performed with enforced oxygen flow, results in the increase of the superconducting transition temperature. Sonication with added Fe(CO)5 produces magnetic Fe2O3 nanoparticles deposited on the surface of YBa2Cu3O7−x (YBCO) granu...

We report on the growth mechanism of YBa2Cu3O7−x. Our study is based on the analysis of ultrathin, YBa2Cu3O7−x layers in c-axis oriented YBa2Cu3O7−x / PrBa2Cu3O7 superlattices. We have found that the release of epitaxial strain in very thin YBCO layers triggers a change in the dimensionality of the growth mode. Ultrathin, epitaxially strained, YBCO layers with thickness below 3 unit cells grow ...

We present a compared experimental investigation of the (a, b) plane vortex-state complex resistivity at 48 GHz in YBa2Cu3O7−δ, SmBa2Cu3O7−δ and Bi2Sr2CaCu2O8+x. In YBa2Cu3O7−δ and SmBa2Cu3O7−δ the field dependence of the response can be consistently described by a combination of flux flow and strong pair breaking due to the presence of lines of nodes in the gap. In Bi2Sr2CaCu2O8+x, by contrast...