Sr 3Sc 2O 5Fe 2As 2 as a possible parent compound for FeAs-based superconductors - Condensed Matter > SuperconductivityReportar como inadecuado

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Abstract: A new compound with the FeAs-layers, namely Sr 3Sc 2O 5Fe 2As 2abbreviated as FeAs-32522, was successfully fabricated. It has a layeredstructure with the space group of I4-mmm, and with the lattice constants a =4.069 $\AA$ and c = 26.876 $\AA$. The in-plane Fe ions construct a squarelattice which is close to that of other FeAs-based superconductors, such asREFeAsO RE = rare earth elements and Ba,SrFe 2As 2. However the interFeAs-layer spacing in the new compound is greatly enlarged. The temperaturedependence of resistivity exhibits a weak upturn in the low temperature region,but a metallic behavior was observed above about 60 K. The magneticsusceptibility shows also a non-monotonic behavior. Interestingly, thewell-known resistivity anomaly which was discovered in all other parentcompounds, such as REFeAsO, Ba,SrFe 2As 2 and Sr,Ca,EuFeAsF and associatedwith the Spin-Density-Wave SDW-structural transition has not been found inthe new system either on the resistivity data or the magnetization data. Thiscould be induced by the large spacing distance between the FeAs-planes,therefore the antiferromagnetic correlation between the moments of Fe ions inneighboring FeAs-layers cannot be established. Alternatively it can also beattributed to the self-doping effect between Fe and Sc ions. The Hallcoefficient R H is negative but strongly temperature dependent in widetemperature region, which indicates the dominance of electrical conduction byelectron-like charge carriers and probably a multi-band effect or a spinrelated scattering effect. It is found that the magnetoresistance cannot bedescribed by the Kohler-s rule, which gives further support to above arguments.

Autor: Xiyu Zhu, Fei Han, Gang Mu, Bin Zeng, Peng Cheng, Bing Shen, Hai-Hu Wen


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