Superconducting fluctuations and anomalous phonon renormalization much above superconducting transition temperature in Ca4Al2O5.7Fe2As2

Kumar, Pradeep and Bera, A and Muthu, DVS and Shirage, PM and Iyo, A and Sood, AK (2012) Superconducting fluctuations and anomalous phonon renormalization much above superconducting transition temperature in Ca4Al2O5.7Fe2As2. In: APPLIED PHYSICS LETTERS, 100 (22).

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Abstract

Raman studies on Ca4Al2O5.7Fe2As2 superconductor in the temperature range of 5K to 300 K, covering the superconducting transition temperature T-c = 28.3 K, reveal that the Raman mode at similar to 230 cm(-1) shows a sharp jump in frequency by similar to 2% and linewidth increases by similar to 175% at T-o similar to 60 K. Below T-o, anomalous softening of the mode frequency and a large decrease by similar to 10 cm(-1) in the linewidth are observed. These precursor effects at T-0 (similar to 2T(c)) are attributed to significant superconducting fluctuations, possibly enhanced due to reduced dimensionality arising from weak coupling between the well separated (similar to 15 angstrom) Fe-As layers in the unit cell. A large blue-shift of the mode frequency between 300 K and 60 K (similar to 7%) indicates strong spin-phonon coupling in this superconductor. (C) 2012 American Institute of Physics. http://dx.doi.org/10.1063/1.4724206]

Item Type:	Journal Article
Publication:	APPLIED PHYSICS LETTERS
Publisher:	AMER INST PHYSICS
Additional Information:	Copyright for this article belongs to the American Institute of Physics
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	06 Jul 2012 10:21
Last Modified:	06 Jul 2012 10:21
URI:	http://eprints.iisc.ac.in/id/eprint/44769

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