Lattice distortions in YBa2Cu3O7–delta thin films grown in situ by sequential ion beam sputtering

We have analyzed epitaxial, c-axis oriented YBa2Cu3O7–delta thin films grown in situ by sequential ion-beam sputtering on (100) SiTiO3 and (100) MgO substrates. X-ray diffraction studies showed the presence of both homogeneous and inhomogeneous lattice distortions along the c-direction. The c-axis lattice parameters ranged from 11.72 to 12.00 Å. The broadening of the (00l) Bragg peaks in excess of the broadening due to finite film thickness was found to be due to inhomogeneous lattice distortions. The overall trend in the data shows an increase of the inhomogeneous strains with the enlargement of the c-axis lattice parameter. The inhomogeneous lattice distortions are interpreted as fluctuations in the c-axis lattice parameter. The resistive transitions were found to be correlated to the lattice distortions. We show correlations between the midpoint Tc and the c-axis lattice parameter and between the transition widths and the inhomogeneous lattice distortions

Correlations between deposition parameters and structural and electrical properties of YBa2Cu3O7–delta thin films grown in situ by sequential ion beam sputtering

We have studied the correlations between deposition parameters and structural and electrical properties of YBa2Cu3O7–delta thin films grown in situ by sequential ion beam sputtering. Epitaxial, c-axis oriented YBa2Cu3O7–delta films were grown both on (100) SrTiO3 and on (100) MgO substrates following the stacking sequence of the ``123'' compound, with deposited layer thicknesses nominally equal to 1 monolayer. The c-axis lattice parameters obtained were larger than the corresponding lattice parameter in bulk samples, even after low-temperature anneals in O2. The transition temperatures were found to decrease with the enlargement of the c-axis lattice parameter. A clear correlation between growth temperature and the value of the c-axis lattice parameter was observed. The c-axis lattice parameter and the x-ray linewidth of Bragg reflections with the G vector along the c-axis were also found to be correlated. This suggests a relationship between the c-axis lattice parameter and the structural coherence of the epitaxial films

Influence of the Cu-Te composition and microstructure on the resistive switching of Cu-Te/Al(2)O(3)/Si cells

In this letter, we explore the influence of the Cu(x)Te(1-x) layer composition (0.2 0.7 leads to large reset power, similar to pure-Cu electrodes, x < 0.3 results in volatile forming properties. The intermediate range 0.5< x < 0.7 shows optimum memory properties, featuring improved control of filament programming using <5 mu A as well as state stability at 85 degrees C. The composition-dependent programming control and filament stability are closely associated with the phases in the Cu(x)Te(1-x) layer and are explained as related to the chemical affinity between Cu and Te. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3621835

Feedborne Salmonella enterica Serovar Jerusalem Outbreak in Different Organic Poultry Flocks in Switzerland and Italy Linked to Soya Expeller

Poultry feed is a leading source of Salmonella infection in poultry. In Switzerland, heat-treated feed is used to reduce Salmonella incursions into flocks in conventional poultry production. By contrast, organic feed is only treated with organic acids. In 2019, the Swiss National Reference Center for Enteropathogenic Bacteria identified the rare serovar S. Jerusalem from samples of organic soya feed. Further, in July 2020, the European Union’s Rapid Alert System for Food and Feed published a notification of the detection of S. Jerusalem in soya expeller from Italy. During 2020, seven S. Jerusalem isolates from seven different poultry productions distributed over six cantons in Switzerland were reported, providing further evidence of a possible outbreak. Using whole-genome sequencing (WGS), S. Jerusalem isolates from feed and from animals in Switzerland were further characterized and compared to S. Jerusalem from organic poultry farm environments in Italy. WGS results showed that feed isolates and isolates from Swiss and Italian poultry flocks belonged to the sequence type (ST)1028, grouped in a very tight cluster, and were closely related. This outbreak highlights the risk of spreading Salmonella by feed and emphasizes the need for a heat-treatment process for feed, also in organic poultry production

Time-resolved temperature measurements during pulsed laser irradiation uslng thin film metal thermometers

In this article, we describe a technique using Nisi and Pt thin film metal thermometers to provide accurate temperature information on a nanosecond time scale during pulsed laser processing of materials. A surface layer of interest is deposited onto the thermometer layer, and temperatures are determined from temperature dependent changes in the metal film&apos;s resistance. Details concerning the design and fabrication of the device structure and experimental considerations in making nanosecond resolved resistance measurements are discussed. Simple analytical estimates are presented to extract quantities such as incident laser energy stored in the sample. Finally, transient temperature data in the thermometer film, in combination with heat flow calculations, allow temperature determination as a function of time and depth into the sample and, additionally, can provide information about material properties of the surface layer