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.
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页数：7
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