A comparative local structure study of pnictide superconductors Ca0.82La0.18FeAs2 (112-type, T-c similar to 40 K) and Ba0.64K0.36Fe2As2 (122-type, T-c similar to 37 K), using room temperature x-ray total scattering measurements is reported. The Fe-As superconducting active layer is found to be globally similar in both the systems consisting of edge-sharing FeAs4/4 tetrahedra as in all the iron-pnictide superconductors discovered so far. Although optimally superconducting, the active layer in these compounds is found to sustain a large local inhomogeneity. These results thus imply that a nanoscopic manipulation of the Fe-As active layer, rather than its isotropic structural tuning, is the key parameter to control the superconducting properties of the iron-based systems. (C) 2015 Elsevier Ltd. All rights reserved.
Comparison of the local structures of Ca0.82La0.18FeAs2 and Ba0.64K0.36Fe2As2 pnictide superconductors using atomic pair distribution function analysis
Iadecola, A;Bernasconi, A;Rispoli, P;
2015-01-01
Abstract
A comparative local structure study of pnictide superconductors Ca0.82La0.18FeAs2 (112-type, T-c similar to 40 K) and Ba0.64K0.36Fe2As2 (122-type, T-c similar to 37 K), using room temperature x-ray total scattering measurements is reported. The Fe-As superconducting active layer is found to be globally similar in both the systems consisting of edge-sharing FeAs4/4 tetrahedra as in all the iron-pnictide superconductors discovered so far. Although optimally superconducting, the active layer in these compounds is found to sustain a large local inhomogeneity. These results thus imply that a nanoscopic manipulation of the Fe-As active layer, rather than its isotropic structural tuning, is the key parameter to control the superconducting properties of the iron-based systems. (C) 2015 Elsevier Ltd. All rights reserved.
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