Resistance flicker noise and current percolation in c-oriented YBa2Cu3O7−x films in the vicinity of Tc

Bobyl, A. V.; Gaevski, Mikhail; Khrebtov, I. A.; Konnikov, S. G.; Shantsev, D. V.; Соловьев, В. А.; Suris, R. A.; Tkachenko, A. D.

doi:10.1016/0921-4534(95)00099-2

Cited by 18 publications

(27 citation statements)

References 46 publications

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“…It is evident that NL of strip1 is characterized by a constant amplitude in the normal state. A noise peak is observed near the transition temperature, a well-known feature related to a superconducting percolation transition and reported for other high- T c compounds272829. Below T c , the NL is strongly suppressed by the superconducting state.…”

Section: Resultssupporting

confidence: 56%

Probing transport mechanisms of BaFe2As2 superconducting films and grain boundary junctions by noise spectroscopy

Barone

Romeo

Pagano

et al. 2014

Sci Rep

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An important step forward for the understanding of high-temperature superconductivity has been the discovery of iron-based superconductors. Among these compounds, iron pnictides could be used for high-field magnet applications, resulting more advantageous over conventional superconductors, due to a high upper critical field as well as its low anisotropy at low temperatures. However, the principal obstacle in fabricating high quality superconducting wires and tapes is given by grain boundaries. In order to study these effects, the dc transport and voltage-noise properties of Co-doped BaFe2As2 superconducting films with artificial grain boundary junctions have been investigated. A specific procedure allows the separation of the film noise from that of the junction. While the former shows a standard 1/f behaviour, the latter is characterized by an unconventional temperature-dependent multi-Lorentzian voltage-spectral density. Moreover, below the film superconducting critical temperature, a peculiar noise spectrum is found for the grain boundary junction. Possible theoretical interpretation of these phenomena is proposed.

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Section: Resultssupporting

confidence: 56%

Probing transport mechanisms of BaFe2As2 superconducting films and grain boundary junctions by noise spectroscopy

Barone

Romeo

Pagano

et al. 2014

Sci Rep

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“…While HTS films carrying small transport currents have been studied previously by the MO method, 4-7 there exists so far no such study focusing on the behavior when I T ϳI c . In this work we show that MO images of self-fields from I T correlated with T c maps obtained by the LTSEM technique 8 can be used to predict the location of burning in HTS films.…”

mentioning

confidence: 79%

“…Using the LTSEM technique, described in detail elsewhere, 8 we made prior to the MO investigation, a map of the local T c for each bridge. Such a T c map of the ''good'' bridge is shown in Fig.…”

mentioning

confidence: 99%

Burning of high Tc bridges

Gaevski

Johansen

Galperin

et al. 1997

Applied Physics Letters

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Burning of superconducting thin film bridges by large transport currents ͑up to densities of 2 ϫ10 7 A/cm 2 ) is investigated by magneto-optical imaging of flux distribution and low-temperature scanning electron microscopy providing T c maps. It is shown that the destruction is preceded by significant penetration of magnetic field inside a weak-pinning region. In bridges containing extended defects magneto-optic investigation is sufficient to locate the incipient burning region. In high-quality bridges free from such defects only a combination of the two techniques will allow prediction of the place of fatal destruction.

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“…In [29] mechanism of cation defect formation is proposed to explain the presence of the swings in T c on composition-property diagrams. Spatially-resolved studies of a YBa 2 Cu 3 O 7Àx thin ®lm bridge using EPMA, LTSEM and magneto-optical (MO)¯ux visualisation have been carried out in [31].…”

Section: Investigation Of Correlation Between Composition T C and Crmentioning

confidence: 99%

“…The results for the HTSC ®lm composition were presented as data points on the quasi-ternary phase diagram CuO-BaO-YO 1.5 (concentrations normalised to the sum of atomic cation concentrations). Such a procedure was used in [29]. It allows the position of a composition on the phase diagram to be de®ne unambiguously and also decreases the errors in determining the composition.…”

Section: Investigation Of Correlation Between Composition T C and Crmentioning

confidence: 99%

Study of Thin Films of High Temperature Superconductors Based on YBaCuO by EPMA

et al. 2000

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An analytical model of an effective atomic number, Z eff , for simultaneous calculation of composition and thickness of ®lms on substrates that allows for backscattering processes is presented. Comparison of dependencies of 9(&z) parameters for ®lm elements on electron beam energy, on atomic numbers of a ®lm and a substrate and on ®lm thickness was done. The errors inherent in EPMA have been determined by comparing experimental data obtained on YBa 2 Cu 3 O 7Àx bulk crystals with model calculations. Possibility of EPMA as an effective technique for investigation of spatially inhomogeneous objects was demonstrated by studying the correlation between composition and local superconducting properties (values of critical temperature and critical current) of these ®lms.The discovery of high temperature superconductivity (HTSC) has resulted in the development of the technology of YBa 2 Cu 3 O 7Àx epitaxial ®lms and in different fundamental and applied studies of their structural and electrophysical properties. The prototypes of practically all known planar devices of the microelectronics have been developed on the base of these ®lms. However, it has been found that even the best YBa 2 Cu 3 O 7Àx ®lms contain signi®cant amounts of different defects and are spatially nonuniform in terms of both their electrophysical properties and composition [1±3]. As a result HTSC microelectronics devices degrade fast, and the yield of those suitable for operation is low [4].Thus, a pressing necessity arose to create technology for the production of high quality YBa 2 Cu 3 O 7Àx ®lms and to develop local high accuracy techniques for determining the composition of the multicomponent structures of the ®lm-substrate type. The use of the EPMA technique has de®nite merits compared with other techniques for the analysis: high spatial resolution of analysis ($ 3 mm), precise observation of the analysed place, availability of well-developed techniques for quanti®cation, and also low sensitivity to artefacts. However, the weaknesses of EPMA technique should be noted: (i) low sensitivity of the analysis (b 0.1±0.001 wt.7), (ii) low possibility to ®x the small difference between concentrations (analytical sensitivity), more then 0.1±0.37 at the concentration of several tens of wt.7 (iii) poor in-depth resolution. Moreover, the procedure for determination of the composition of the ®lms of thicknesses smaller than the X-ray generation depth (R x ) (HTSC ®lms are related just to this class of object) are not up to now suf®ciently developed. The present work is a review devoted to our investigations of HTSC YBa 2 Cu 3 O 7Àx epitaxial ®lms and contains a thorough experimental veri®cation on the correlations between composition and local superconducting properties. Procedure for Determining Composition and Thickness of Films (Z eff Model)In the case when the ionization path of an electron is greater than the ®lm thickness, the use of a model

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Resistance flicker noise and current percolation in c-oriented YBa2Cu3O7−x films in the vicinity of Tc

Cited by 18 publications

References 46 publications

Probing transport mechanisms of BaFe2As2 superconducting films and grain boundary junctions by noise spectroscopy

Probing transport mechanisms of BaFe2As2 superconducting films and grain boundary junctions by noise spectroscopy

Burning of high Tc bridges

Study of Thin Films of High Temperature Superconductors Based on YBaCuO by EPMA

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