Cr doping effects on structure and superconductivity of Ba2Ti2Fe2As4O

Abstract Chemical doping effects on structure and superconductivity were studied by introducing Cr at Fe sites in Ba 2 Ti 2 Fe 2 As 4 O, where Cr 2+ can play dual role as impurities and hole dopants. Ba 2 Ti 2 (Fe 1-x Cr x ) 2 As 4 O (0 ≤ x ≤ 8%) compounds are synthesized by a solid-state reaction and characterized with x-ray diffraction, electric resistivity and magnetization measurements. It is observed that the Cr dopants induce lattice expansion and local structure distortion, and significantly suppress the superconducting transition temperature T c . In the meantime, the residual resistivity is found steadily increased with Cr doping. Comprehensive analyses show that T c suppression is strongly correlated with the impurity-induced scattering to electrons, which can be fitted with the Abrikosov-Gor'kov-like scaling function.