Re-entrance of resistivity due to the interplay of superconductivity and magnetism in \ce{Eu_{0.73}Ca_{0.27}(Fe_{0.87}Co_{0.13})2As2}

Abstract

By simultaneous Co and Ca-doping we were able to obtain an \ce{EuFe2As2}-based compound with superconductivity appearing above the antiferromagnetic order of \ce{Eu^{2+}} magnetic moments. However, as soon as the antiferromagnetic order appears a re-entrance behavior is observed \textemdash{} instead of zero resistivity and diamagnetic signal down to the temperature of \unit[2]{K}. By investigating magnetization, ac susceptibility and electrical transport properties of \ce{Eu_{0.73}Ca_{0.27}(Fe_{0.87}Co_{0.13})2As2} and comparing them to previously studied M\"ossbauer effect and neutron scattering measurements of this and similar compounds an explanation of such behavior is proposed.Comment: Main paper of 9 pages with 9 figures with Supplementary Material