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Advances in Condensed Matter Physics
Volume 2016, Article ID 5470429, 10 pages
http://dx.doi.org/10.1155/2016/5470429
Research Article

Theoretical Study of Upper Critical Magnetic Field () in Multiband Iron Based Superconductors

1Department of Physics, Adigrat University, P.O. Box 50, Adigrat, Ethiopia
2Department of Physics, College of Science, Bahir Dar University, P.O Box 79, Bahir Dar, Ethiopia

Received 23 August 2016; Revised 25 October 2016; Accepted 9 November 2016

Academic Editor: Prasenjit Guptasarma

Copyright © 2016 Tsadik Kidanemariam and Gebregziabher Kahsay. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This research work focuses on the theoretical investigation of the upper critical magnetic field, ; Ginzburg-Landau coherence length, ; and Ginzburg-Landau penetration depth, , for the two-band iron based superconductors , , and LiFeAs. By employing the phenomenological Ginzburg-Landau (GL) equation for the two-band superconductors , , and LiFeAs, we obtained expressions for the upper critical magnetic field, ; GL coherence length, ; and GL penetration depth, , as a function of temperature and the angular dependency of upper critical magnetic field. By using the experimental values in the obtained expressions, phase diagrams of the upper critical magnetic field parallel, , and perpendicular, , to the symmetry axis (-direction) versus temperature are plotted. We also plotted the phase diagrams of the upper critical magnetic field, versus the angle . Similarly, the phase diagrams of the GL coherence length, , and GL penetration depth, , parallel and perpendicular to the symmetry axis versus temperature are drawn for the superconductors mentioned above. Our findings are in agreement with experimental observations.