In-field Conductivity Fluctuations in Ba{sub 0.72}K{sub 0.28}Fe{sub 2}As{sub 2} Single Crystals
- University of Wollongong, Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, Faculty of Engineering (Australia)
Fluctuations in the conductivity of Ba{sub 0.72}K{sub 0.28}Fe{sub 2}As{sub 2} single crystal are studied systematically by resistance measurements as a function of temperature and magnetic field. A clear Maki−Thompson and Aslamakov−Larkin (MT–AL) two- to three-dimensional (2D–3D) crossover is found on the excess conductivity (Δσ) curves as the temperature approaches the superconducting critical temperature, T{sub c}. 3D fluctuations in superconductivity are realized near T{sub c} that are well fitted to experimental data by the 3D Aslamazov–Larkin theory. The Maki–Thompson model shows a 2D conductivity fluctuation above the 2D-3D temperature transition, T{sub 0}, which depends on magnetic field. Results show that the 2D-3D dimensional crossover moves to lower temperature with increasing magnetic field. The values of the transition temperature and the crossover in the reduced temperature, ln(ε{sub 0}), as functions of magnetic field were used to determine the coherence length and the lifetime, τ{sub φ}, of the fluctuational pairs at the temperature of 35 K. Analysis of the Ba{sub 0.72}K{sub 0.28}Fe{sub 2}As{sub 2} single crystal gives a value of 3.76 × 10{sup − 12} s for the τ{sub φ} in the absence of magnetic field and it decreases to 2.4 × 10{sup − 12} s in magnetic field of 13 T.
- OSTI ID:
- 22773875
- Journal Information:
- Journal of Superconductivity and Novel Magnetism, Vol. 31, Issue 8; Other Information: Copyright (c) 2018 Springer Science+Business Media, LLC, part of Springer Nature; http://www.springer-ny.com; Country of input: International Atomic Energy Agency (IAEA); ISSN 1557-1939
- Country of Publication:
- United States
- Language:
- English
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