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Title: In-field Conductivity Fluctuations in Ba{sub 0.72}K{sub 0.28}Fe{sub 2}As{sub 2} Single Crystals

Abstract

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.

Authors:
 [1];  [2]
  1. Ferdowsi University of Mashhad, Department of Physics, Faculty of Science (Iran, Islamic Republic of)
  2. University of Wollongong, Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, Faculty of Engineering (Australia)
Publication Date:
OSTI Identifier:
22773875
Resource Type:
Journal Article
Journal Name:
Journal of Superconductivity and Novel Magnetism
Additional Journal Information:
Journal Volume: 31; Journal 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); Journal ID: ISSN 1557-1939
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BARIUM COMPLEXES; COHERENCE LENGTH; CRITICAL TEMPERATURE; EXPERIMENTAL DATA; IRON ARSENIDES; MAGNETIC FIELDS; MONOCRYSTALS; POTASSIUM COMPLEXES; SUPERCONDUCTIVITY; TEMPERATURE DEPENDENCE; THREE-DIMENSIONAL LATTICES

Citation Formats

Ghorbani, S. R., E-mail: sh.ghorbani@um.ac.ir, and Wang, X. L. In-field Conductivity Fluctuations in Ba{sub 0.72}K{sub 0.28}Fe{sub 2}As{sub 2} Single Crystals. United States: N. p., 2018. Web. doi:10.1007/S10948-017-4522-6.
Ghorbani, S. R., E-mail: sh.ghorbani@um.ac.ir, & Wang, X. L. In-field Conductivity Fluctuations in Ba{sub 0.72}K{sub 0.28}Fe{sub 2}As{sub 2} Single Crystals. United States. doi:10.1007/S10948-017-4522-6.
Ghorbani, S. R., E-mail: sh.ghorbani@um.ac.ir, and Wang, X. L. Wed . "In-field Conductivity Fluctuations in Ba{sub 0.72}K{sub 0.28}Fe{sub 2}As{sub 2} Single Crystals". United States. doi:10.1007/S10948-017-4522-6.
@article{osti_22773875,
title = {In-field Conductivity Fluctuations in Ba{sub 0.72}K{sub 0.28}Fe{sub 2}As{sub 2} Single Crystals},
author = {Ghorbani, S. R., E-mail: sh.ghorbani@um.ac.ir and Wang, X. L.},
abstractNote = {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.},
doi = {10.1007/S10948-017-4522-6},
journal = {Journal of Superconductivity and Novel Magnetism},
issn = {1557-1939},
number = 8,
volume = 31,
place = {United States},
year = {2018},
month = {8}
}