Thermal and voltage activated excess 1/f noise in FeTe0.5Se0.5 epitaxial thin films

被引：24

作者：

Barone, C. ^{[1
,2
]}

Pagano, S. ^{[1
,2
]}

Pallecchi, I. ^{[3
]}

Bellingeri, E. ^{[3
]}

Putti, M. ^{[4
,5
]}

Ferdeghini, C. ^{[3
]}

机构：

[1] Univ Salerno, Dipartimento Matemat & Informat, I-84084 Salerno, Italy

[2] Univ Salerno, CNR SPIN Salerno, I-84084 Salerno, Italy

[3] CNR SPIN Genova, I-16152 Genoa, Italy

[4] Univ Genoa, Dipartimento Fis, I-16146 Genoa, Italy

[5] Univ Genoa, CNR SPIN Genova, I-16146 Genoa, Italy

来源：

PHYSICAL REVIEW B | 2011年 / 83卷 / 13期

关键词：

SUPERCONDUCTOR;

D O I：

10.1103/PhysRevB.83.134523

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We report on measurements of electric transport and voltage noise in FeTe0.5Se0.5 epitaxial thin films. Detailed structural investigations demonstrate the high quality of the samples, also testified by a superconducting transition temperature of 18 K, larger than the value observed for bulk compounds. An unusual dependence of the 1/f noise is found by varying the applied voltage and the temperature. Above a threshold voltage the 1/f noise shows a nonquadratic dependence on applied voltage with a temperature-dependent exponent. Conversely, at low voltages the 1/f noise amplitude follows always a quadratic law. In the superconductive transition region, a simple percolative model allows one to estimate the dimensionality of the system, which is found to be two-dimensional, with a critical exponent similar to values reported for other high-T-c superconductors. The experimental findings on noise properties give evidence of unusual transport processes, occurring in this new superconducting material, and can provide useful information on possible conduction mechanisms.

引用

页数：7

共 31 条

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