Superconducting properties in granular aluminum films near percolation threshold

Yamada, Kazumasa; Fujiki, Hiroyuki; Shinozaki, B.; Kawaguti, T.

doi:10.1016/s0921-4534(00)01768-8

Cited by 4 publications

(8 citation statements)

References 20 publications

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“…In the R-T curve at a constant H, T C ͑H͒ was defined as a temperature at which half of R ᮀ N was restored. 4 We had noted that we obtain the similar power law H C2 -T relation for percolative films by the use of different criterion T C ͑H͒. Strictly speaking, however, the H C2 -T relation, namely, the temperature dependence of H C2 near T C seems to depend on this criterion.…”

Section: A Magnetoconductance Above T Csupporting

confidence: 53%

“…11 We have investigated H C2 ͑T͒ in 2D granular Al films in the previous work. 4 The index increases steeply near characteristic sheet resistance R * Ϸ 1.5 k⍀ and approaches Ϸ0.9 with increase of R ᮀ . In films with R ᮀ Ͼ R * , the excess conductance Ј due to superconducting fluctuations decreases drastically as compared with that estimated from theories for homogeneous films.…”

Section: Introductionmentioning

confidence: 94%

“…We have mentioned details of measurement method and d dependence of R ᮀ . 4 According to the TEM micrograph of thin Al-Al 2 O 3 film taken by Laibowitz et al, 26 clusters of Al-Al 2 O 3 films have a labyrinthlike structure.…”

Section: Sample Preparationsmentioning

confidence: 99%

“…For these films, homogeneousinhomogeneous crossover in granular superconductors has been investigated by using percolation models. [4][5][6] For homogeneous dirty superconductors, the superconducting correlation length S is simply given by S 2 = D GL , where D and GL are the diffusion constant and the Gintzburg-Landau relaxation time GL = ប / ͕8k B ͉T C − T͉͖, respectively. However, electron diffusion in percolative superconductors is different from that in homogeneous ones.…”

Section: Introductionmentioning

confidence: 99%

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Weak localization and magnetoconductance in percolative superconducting aluminum films

2004

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In order to investigate the crossover from a homogeneous behavior to an inhomogeneous (percolative) one, the temperature T and magnetic field H dependence of the sheet resistance R ᮀ have been measured for two-dimensional granular aluminum films. Fitting the theory to data on magnetoconductance near T C with use of the diffusion constant D͑T͒ as a fitting parameter, we have obtained the anomalous T-dependent diffusion constant D. From D͑T͒, the electron diffusion index , a certain critical exponent in the percolation theory, has been obtained. In the relation R ᮀ − , the value of varies abruptly near 1.5 k⍀. This behavior suggests the abovementioned crossover is similar to our previous results determined from the T dependence of the upper critical magnetic field. For percolative films at H = 5 T, we have found the strong R ᮀ dependence of the prefactor ␣ T in the expression = ͓␣ T e 2 / ͑2 2 ប͔͒ln T + 0 . The relation ␣ T ϰ 1/R ᮀ can be explained qualitatively by a model of scaling law for percolation.

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Section: A Magnetoconductance Above T Csupporting

confidence: 53%

Section: Introductionmentioning

confidence: 94%

Section: Sample Preparationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Weak localization and magnetoconductance in percolative superconducting aluminum films

2004

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“…38 Also, T c strongly depends on the inter-grain spacing. 39 For example, the T c1 (T c2 ) of the Nb island arrays in Ref.…”

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confidence: 99%

Superconductivity in textured Bi clusters/Bi2Te3 films

Tzeng

Chen

et al. 2014

Apl Materials

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We report superconductivity at an onset critical temperature below 3.1 K in topological insulator ∼200-nm-thick Bi2Te3 thin films grown by pulsed laser deposition. Using energy-dispersive X-ray spectroscopy elemental mapping and Auger electron spectroscopy elemental depth profiling, we clearly identified bismuth (Bi) precipitation and Bi cluster signatures. Superconductivity in the Bi2Te3 films was attributed to the proximity effect of Bi clusters precipitated on the surface of the Bi2Te3 films.

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