Influence of substitutional disorder on the electrical transport and the superconducting properties of Fe1+zTe1-x-ySexSy

M. G. RODRÍGUEZ; G. POLLA; C. P. RAMOS; C. ACHA

JOURNAL OF ALLOYS AND COMPOUNDS

ELSEVIER SCIENCE SA

Lugar: Amsterdam; Año: 2015 vol. 649 p. 1031 - 1036

0925-8388

 We have carried out an investigation of the structural, magnetic, transport and superconducting properties of FeTe1-x-ySexSy ceramic compounds, for some specific Se (0< x <0.45) and S (0.01 < y <0.12) contents. The incorporation of Se and S to the FeTe structure produces a progressive reduction of the crystallographic parameters as well as different degrees of structural disorder associated with the differences of the ionic radius of the substituting cations. A small content of Fe7Se8 and Fe3O4 as minor impurities was detected for all the samples with a clear influence on the magnetic properties of the normal state. In contrast, the electric transport properties of the normal state are practically not affected by its presence, while the structural disorder seems to correlate with a variable range hopping conducting regime observed at temperatures T > 200 K. We find that the depression of the superconducting properties for the samples with higher Te content can be associated with the presence of dipolar magnetic interactions.