143 research outputs found
Growth of ultrathin twin-free b-oriented YBa2Cu3O7–x films
No full textTwin-free b-oriented YBa2Cu3O7–x films with a thickness less than 40 nm have been epitaxially grown on (100)SrLaGaO4 crystals. Based on the temperature dependence of resistance, the onset temperature of the transition to the superconducting state is found to be 90 K; the transition width is 4 K. The film growth has been performed in two stages. A (100)PrBa2Cu3O7 – x buffer layer was previously grown on a (100)SrLaGaO4 substrate by rf magnetron sputtering in an Ar–O2 gas mixture at a continuous and monotonic increase in temperature from 660 to 830°C. The main YBa2Cu3O7 – x film was grown on the buffer layer surface by pulsed laser deposition in an oxygen medium at a fixed temperature (800°C). The above processes were implemented in different chambers, which were connected by a vacuum channel for transporting samples. Both films were grown in situ, without contacting atmosphere in all growth stages. An X-ray diffraction study has shown that the YBa2Cu3O7 – x films are single-crystal and free of precipitates of other phases and domains of other orientations
Growth of twin-free b-oriented YBa2Cu3O7−x films
No full textYBa2Cu3O7−x films of b orientation have been grown on the surface of (100)SrLaGaO4 crystal. It is demonstrated that the films pass to the superconducting state at a temperature of 89 K. In the non superconducting region, the film resistance decreases linearly with a decrease in temperature at a rate of 30 Ω per 100°C. According to the X-ray diffraction data on the crystallographic structure of the YBa2Cu3O7−x films, they are single-crystal and b-oriented. It is shown that the films contain no domains of other crystallographic orientations, including a-oriented domains. Therefore, the films are free of structural twins
Temperature sensitivity and noise of Josephson detector on bicrystal sapphire substrates at 77 K
No full textCitation for the published paper: Tarasov, M. ; Stepantsov, E. ; Kalaboukhov, A. (2007) "Temperature sensitivity and noise of Josephson detector on bicrystal sapphire substrates at 77 K". JETP Letters, vol. 86(11), http://d
Study of in-plane electrical transport anisotropy of a-axis oriented YBa2Cu3O7-δ nanodevices
No full textIn the present work, we report the growth of fully untwinned high-quality a-axis-oriented YBa2Cu3O7-δ films on (100) SrLaGaO4 substrates by using PrBa2Cu3O7-δ as a buffer layer. We also fabricated nanowires at different angles γ with respect to the [0,1,0] direction of the substrate and studied the in-plane anisotropy of the critical current density, which we explained by considering the anisotropy in the coherence length ξ and London penetration depth λL. Finally, half-integer Shapiro-like steps measured in slightly underdoped c-axis oriented (γ=90°) nanowires point towards a different transport regime, which could shed light on intriguing issues of high-critical-temperature superconductors
Investigation into the growth and structure of thin-film solid solutions of iron-based superconductors in the FeSe0.92-FeSe0.5Te0.5 system
No full textThin films of FeSe0.92 and FeSe0.5Te0.5 iron chalcogenide superconductors and solid solutions containing these components in different ratios have been grown on the surface of LaAlO 3 (10 bar 12) crystals by pulsed laser deposition. Films of solid solutions have been deposited by simultaneous laser ablation from two targets of the FeSe0.92 and FeSe0.5Te0.5 stoichiometric compositions onto one substrate. An X-ray diffraction study of the film structure shows that the films grown are epitaxial and their lattice parameters regularly vary with the ratio of the deposited components, which was controllably varied by changing the ablation intensities from the targets. © 2013 Pleiades Publishing, Ltd
Potential of Rural Cultural Leisure in Belarus
No full textThe solution to the problem of preserving the identity of the cultural traditions of the Belarus village is to actualize the socio-cultural potential of rural regions, to reveal the uniqueness of the resources of each territory and their cultural specialization, to find forms of involvement of the population in the processes of socio-cultural development of territories
Microstructure and properties of artificial grain boundaries in epitaxial YBA2Cu3O7-δ thin films grown on [001] tilt YZrO2 bicrystals
No full textThe microstructure of artificial grain boundaries in YBa2Cu3O7-δ (YBCO) thin films grown on [001] tilt YZrO2 (YSZ) bicrystal substrates has been characterized using transmission electron microscopy and atomic force microscopy. Despite a relatively straight morphology of the substrate boundaries, the film boundaries were wavy. The waviness was a result of the combined effects of grooving at the substrate boundaries prior to the film deposition and an island-growth mechanism for YBCO on YSZ substrates. The dihedral angle of the groove walls varied with the misorientation angle and depended on the symmetry of the substrate boundary. The amplitudes of the film boundary waviness compared well with the widths of the grooves. In addition, the grooves induced local bending of the YBCO lattice planes and additional tilt components perpendicular to the c-axis close to the film boundaries. © 1995
Engineering underdoped CuO nanoribbons in nm-thick -axis YBaCuO films
No full textIn underdoped cuprate high superconductors, various local
orders and symmetry breaking states, in addition to superconductivity, reside
in the CuO planes. The confinement of the CuO planes can therefore play
a fundamental role in modifying the hierarchy between the various orders and
their intertwining with superconductivity. Here we present the growth of
-axis oriented YBaCuO films, spanning the whole
underdoped side of the phase diagram. In these samples, the CuO planes are
confined by the film thickness, effectively forming unit-cell-thick
nanoribbons. The unidirectional confinement at the nanoscale enhances the
in-plane anisotropy of the films. By X-ray diffraction and resistance vs
temperature measurements, we have discovered the suppression of the
orthorhombic-to-tetragonal transition at low dopings, and a very high
anisotropy of the normal state resistance in the - plane, the latter
being connected to a weak coupling between adjacent CuO nanoribbons. These
findings show that the samples we have grown represent a novel system,
different from the bulk, where future experiments can possibly shed light on
the rich and mysterious physics occurring within the CuO planes
Microstructure of epitaxial YBa2Cu3O7-δ thin films on (001)-tilt Y-ZrO2 bicrystals
No full textThe microstructures of the grain boundaries in epitaxial YBa2Cu3O7-δ thin films grown on [001]-tilt yttria-stabilized ZrO2 bicrystal substrates were characterized by TEM and at. force microscopy. The exact boundary plane geometries of the bicrystal substrates were not transferred to the films which instead had wiggling grain boundaries. [on SciFinder(R)
SOWING IN TEARS AND REAPING IN JOY: PSALM 125. 5–6 IN THE INTERPRETATION OF SAINT AUGUSTINE
No full textSaint Augustine of Hippo often quoted the last verses of the 125th psalm and several times meditated its content in his tractates and sermons. The author of this article examines a selection of these citations, in which the verses are not only quoted but also, both directly and indirectly, commented upon. In his exposition of the Epistle to the Galatians, Augustine merely mentions the fact of the possibility of a spiritual understanding of the passage. The most thorough and most complete exposition of this passage is found in Augustine’s 31st Homily. This exposition is actually more thematic than exegetical. The main points of this homily include the idea of an explanation of the various reasons for tears shed by people during their earthly lives (the tears of martyrs, the tears deriving from earthly pains and sorrows, the tears of a just man separated from his God). But the most profound interpretation of these psalm verses is found in Augustines’s exposition of Psalm 125 (11–13). Here Augustine enumerates all the good actions which he considers to be symbolized by the idea of sowing (almsgiving, aid rendered through deed, aid rendered through word, the mere desire to render aid). At the same time, Augustine does not develop in this exposition the idea of forgiving offences as a type of almsgiving. On the other hand he reveals the essence of good works as charity and the Goal of those who practise good works as the union of the faithful soul with Christ. The author includes a Russian translation of the 31st homily at the end of his article
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