Superconducting transition temperatures in electronic and magnetic phase diagram of a superconductor, Sr2VFeAsO3-delta

We unveil magnetic phases and superconducting transition temperatures (Tc) in an iron-based superconductor with a thick-blocking layer of a perovskite-related transition metal oxide, Sr2VFeAsO3-delta (21113V). 21113V exhibits a superconducting phase in 0.031 =< delta =< 0.145 at temperatures (T) < 37.1 K. Antiferromagnetic (AFM) iron sublattice are observed in 0.267 =< delta =< 0.664. A mixed valent vanadium exhibits a dominant AFM phase in 0.031 =< delta =< 0.088, while a partial ferrimagnetic (Ferri.) phase of the vanadium appears in 0.124 =< delta =< 0.664. The partial Ferri. phase becomes the most dominant for delta~0.267, in which the Fe shows AFM phase at T < 20 K. A volume fraction of the superconducting phase is suppressed by increasing of spontaneous magnetic moments due to the partial Ferri. vanadium; i.e the magnetic phase of the vanadium dominates superconductivity in 21113V. The Tc-delta curve shows two maxima. The lower maximum of Tc are observed for delta = 0.073. It is noted that the highest Tc of 21113V appears for delta = 0.145, which exists in a phase boundary between AFM and the partial Ferri. phases of the vanadium. 21113V is a platform to verify new mechanism for enhancing Tc in iron-based superconductors.