Influence of the Fluoride Atoms Doping on the FeSe Superconductor

A D Bortolozo,C A M Dos Santos,A D Gueiros,L M S Alves

doi:10.4236/msa.2012.39090

Abstract

It is reported the influence of the interstitial atoms doping on the FeSe superconductor. Polycrystalline samples with FeSeFx and FeSeBx nominal compositions were prepared by solid state reaction. An enhancement of the superconducting transition temperature was observed in the temperature dependence of the electrical resistivity curve to the FeSeF0.015 sample. R(T) data display superconducting behavior close to 12 K. The Tc increased with F doping by up to 50%. In contrast, boron doping no change the superconducting properties of the FeSe compound. As the FeSeFx and FeSeBx system the fluoride doping introduce a negative chemical pressure in the FeSe superconductor. This fact suggests that fluoride doping have changed the electronic properties of the FeSe phase.

Highlights

Since the surprisingly discovery of superconductivity in high temperature of 55 K to the fluorine-doped rare-earth iron oxyarsenides, REFeAs1–xFx, many research has been made on new superconducting materials [1,2,3,4]
They showed that nonsuperconducting Fe1+δSe is not magnetically ordered down to 5 K and it is destroyed by very small changes in stoichiometry
We found that the FeSe + 0.5% FeF3 shows superconducting transition like Fe (SeTe) solid solution

Summary

Introduction

Since the surprisingly discovery of superconductivity in high temperature of 55 K to the fluorine-doped rare-earth iron oxyarsenides, REFeAs1–xFx, many research has been made on new superconducting materials [1,2,3,4]. The new materials class has Fe and share a common structural feature. FeSe system is one of the most attracting systems, because it has the simplest crystal structure among the ironbased superconductors [5,6]. McQueen has been shown that superconductivity in Fe1+δSe is destroyed by very small changes in stoichiometric [7]. They showed that nonsuperconducting Fe1+δSe is not magnetically ordered down to 5 K and it is destroyed by very small changes in stoichiometry. Immediate instability against an ordered magnetic state should not be considered as intrinsic characteristic [7]

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Results

Conclusion