Cr doping effects on structure and superconductivity of Ba2Ti2Fe2As4O

Chemical doping effects on structure and superconductivity were studied by introducing Cr at Fe sites in Ba2Ti2Fe2As4O, where Cr2+ can play dual role as impurities and hole dopants. Ba2Ti2(Fe1-xCrx)2As4O (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...