The practical doping principles of tuning antiferromagnetic state in BiMn2O5 ceramics

A series of Bi 1- x Sr x Mn 2- y Ti y O 5 ceramics were synthesized via a conventional solid-state reaction method, and their crystal structures and magnetic properties were investigated. The strong correlation between the magnetic behavior and mixed–valence states of the Mn ions was characterized by a vibrating sample magnetometer and XPS measurements. Here, we disclose the equation of band angle, length, and magnetic ground state, which is ascribed to the doping element and concentration. Magnetic characterization reveals that Sr- doped ( x = 0.3) ceramics exhibit oxygen vacancy-induced ferromagnetic behaviors, which is understood by the bound magnetic polarons mechanism. To clarify the origin of ferromagnetic behavior in non–magnetic doped ceramics, contrast experiments of temperature-dependent magnetic traits of Ti-doped ceramics were analyzed. Furthermore, the tunable Néel temperature is ascribed to the large effective exchange coupling constant. The significance of this work is that we demonstrate an effective tool for manipulating the antiferromagnetic state and offer practical doping principles.