Compositionally controlled semimetal to superconducting transition in NaF doped LaOFeAs: enhancement in Tc due to Na-doping

Prakash, J. ; Singh, S. J. ; Ahmed, J. ; Patnaik, S. ; Ganguli, A. K. (2009) Compositionally controlled semimetal to superconducting transition in NaF doped LaOFeAs: enhancement in Tc due to Na-doping Physica C: Superconductivity, 469 (7-8). pp. 300-304. ISSN 0921-4534

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Official URL: http://www.sciencedirect.com/science/article/pii/S...

Related URL: http://dx.doi.org/10.1016/j.physc.2009.03.002

Abstract

We report the synthesis of LaOFeAs based oxypnictide superconductors (La1-xNaxO1-xFxFeAs) using sodium fluoride as a fluorinating agent. NaF doping leads to a systematic decrease in both the a and c lattice parameters. Resistivity measurements show the onset resistivity transition temperature at 30.9 (±0.05) K and corresponding Meissner transition at 28 (±0.05) K in La0.85Na0.15O0.85F0.15FeAs which is highest in LaOFeAs type superconductors synthesized at ambient pressure. Further increase of NaF content in LaOFeAs leads to suppression of Tc. The above superconductors show a negative value of the Seebeck coefficient which indicates that electrons are the dominant charge carriers.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Oxypnictides; Superconductivity
ID Code:91642
Deposited On:23 May 2012 14:24
Last Modified:23 May 2012 14:24

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