Microstructural investigation of the growth of YBa2Cu3O7−x/Nd2CuO4/YBa2Cu3O7−x trilayered films on LaSrGaO4 substrates

Li, Y.H.; Staton‐Bevan, A. E.; Trajanovic, Z.; Takeuchi, Ichiro; Venkatesan, T.

doi:10.1016/0921-4534(96)00323-1

Cited by 4 publications

(7 citation statements)

References 18 publications

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“…6. Let us note that lim h→∞ τ h+1 τ h = e 1/e ≈ 1.44 (10) thus for large h the birth time of new levels increases exponentially, τ h ∼ exp(h/e) The mean time τ 2 can be analytically calculated by considering the exact process (not the averages). We start with one node at hierarchy level h = 0.…”

Section: Hierarchy Level Birth Timementioning

confidence: 99%

“…It makes highly relevant the question how the imposed information limit -the limit in the amount of information new nodes possess about entire system -impacts the growth process of a network. In fact, a preferential attachment where information is local and limited has already been studied before [10][11][12]. Therein new nodes could attach only to a random subset of all nodes.…”

Section: Introductionmentioning

confidence: 99%

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Information slows down hierarchy growth

et al. 2014

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We consider models of growing multi-level systems wherein the growth process is driven by rules of tournament selection. A system can be conceived as an evolving tree with a new node being attached to a contestant node at the best hierarchy level (a level nearest to the tree root). The proposed evolution reflects limited information on system properties available to new nodes. It can also be expressed in terms of population dynamics. Two models are considered: a constant tournament (CT) model wherein the number of tournament participants is constant throughout system evolution, and a proportional tournament (PT) model where this number increases proportionally to the growing size of the system itself. The results of analytical calculations based on a rate equation fit well to numerical simulations for both models. In the CT model all hierarchy levels emerge but the birth time of a consecutive hierarchy level increases exponentially or faster for each new level. The number of nodes at the first hierarchy level grows logarithmically in time, while the size of the last, "worst" hierarchy level oscillates quasi log-periodically. In the PT model the occupations of the first two hierarchy levels increase linearly but worse hierarchy levels either do not emerge at all or appear only by chance in early stage of system evolution to further stop growing at all. The results allow to conclude that information available to each new node in tournament dynamics restrains the emergence of new hierarchy levels and that it is the absolute amount of information, not relative, which governs such behavior.

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Section: Hierarchy Level Birth Timementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Information slows down hierarchy growth

et al. 2014

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“…This property of a superconducting compound is very important and promising for physical investigations and device applications [2][3][4][5][6][7][8]. Nowadays, most important applications of epitaxial superconducting YBCO films are associated with microwave electronic devices, e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Nowadays, most important applications of epitaxial superconducting YBCO films are associated with microwave electronic devices, e.g. power band-pass filters [3][4][5], high current-transfer circuits [6] and low-signal electronic devices, such as SQUID magnetometers and bolometers [6][7][8]. Structures with c ⊥ orientation (or (001) films) find application in power devices, because in this case the current direction lies in the film plane and thus coincides with the a−b plane of the YBCO crystal lattice.…”

Section: Introductionmentioning

confidence: 99%

Influence of growth rate on the structural orientation of YBCO superconducting films

Karmanenko

1999

Supercond. Sci. Technol.

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Superconducting films were grown by DC magnetron sputtering of a stoichiometric target at varied pressure (p =5-100 Pa) of argon/oxygen mixture and substrate (MgO(100), , ) temperature K. Film axis orientation and crystal quality were investigated using Raman spectroscopy and medium energy ion backscattering technique. The pressure and substrate temperature determine the growth rate and the crystallographic orientation of YBCO films. At a critical value of about 1.5-2.0 nm , films of mixed orientation are formed. At higher than the critical value, the films show orientation, and growth at rates lower than 1.5 nm gives -oriented films. Correspondingly, at low nm , truly epitaxial films are formed and this kind of structure may be preserved up to 1-m film thickness. A kinetic study allowed estimating the coefficients of surface diffusion in the indicated temperature range: , and . The data obtained are discussed and compared with the known values.

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“…It makes YBCO thin films a perfect candidate for various electric power applications [18][19][20] . In addition, applications of YBCO thin films are associated with microwave electronic devices 21,22 and low signal electronic devices 19,23,24 . The critical current density of these films (like any type-II superconducting material) is governed by pinning of superconducting vortices by crystal defects.…”

Section: Introductionmentioning

confidence: 99%

Significant tunability of thin film functionalities enabled by manipulating magnetic and structural nano-domains

Golovchanskiy

Pan

Fedoseev

et al. 2014

Applied Surface Science

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The influence of laser frequency on the structure and physical properties of thin films grown by pulsed laser deposition has been studied. Different types of thin films, hard ferromagnetic FePt L10 and quasi-single crystal superconducting YBa2Cu3O7 (YBCO), have been used for demonstration of the effect. Significant structural modifications have been obtained for the films with similar thicknesses. These modifications are shown to dramatically control their corresponding properties, providing an instrumental ability for tuning the practical characteristics of the films by changing the laser frequency of their deposition. In particular, 20-fold increase of coercive field and modification of demagnetization mechanism are obtained for FePt films by varying the frequency from 1 Hz to 6 Hz. Over a similar frequency range, a strong dependence on the laser frequency is discovered for the YBCO films for the critical current density behavior as a function of the applied magnetic field [ Jc(Ba)] with the unexpected reversal of Jc(Ba) curves with temperature. The mechanisms of structure modifications and corresponding property variations are proposed. The influence of laser frequency on the structure and physical properties of thin films grown by pulsed laser deposition has been studied. Different types of thin films, hard ferromagnetic FePt L10 and quasi-single crystal superconducting YBa2Cu3O7 (YBCO), have been used for demonstration of the effect. Significant structural modifications have been obtained for the films with similar thicknesses. These modifications are shown to dramatically control their corresponding properties, providing an instrumental ability for tuning the practical characteristics of the films by changing the laser frequency of their deposition. In particular, 20-fold increase of coercive field and modification of demagnetization mechanism are obtained for FePt films by varying the frequency from 1 Hz to 6 Hz. Over a similar frequency range, a strong dependence on the laser frequency is discovered for the YBCO films for the critical current density behaviour as a function of the applied magnetic field [Jc(Ba)] with the unexpected reversal of Jc(Ba) curves with temperature. The mechanisms of structure modifications and corresponding property variations are proposed.

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Microstructural investigation of the growth of YBa2Cu3O7−x/Nd2CuO4/YBa2Cu3O7−x trilayered films on LaSrGaO4 substrates

Cited by 4 publications

References 18 publications

Information slows down hierarchy growth

Information slows down hierarchy growth

Influence of growth rate on the structural orientation of YBCO superconducting films

Significant tunability of thin film functionalities enabled by manipulating magnetic and structural nano-domains

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