Ba2+ doping effect on the charge ordering of Bi0.5Sr0.5−xBaxMnO3 (–0.30)

Polycrystalline samples of Ba-doped Bi0.5Sr0.5MnO3 have been prepared by a standard solid-state reaction. The influence of the Ba doping effect on the structural, macro-magnetic, and micro-magnetic properties of the compounds has been investigated experimentally. All the samples crystallize in an orthorhombic structure and the lattice parameters increase continuously with increasing Ba doping level. Due to the increase of the e g electron bandwidth resulting from the Ba doping, the charge-ordering (CO) transition temperature T CO decreases noticeably. Both the macro-magnetic and the micro-magnetic data show that, in all the samples, only a paramagnetic (PM)/charge-disordered state exists above the CO transition, and only a charge-ordered state coexists with the PM matrix below the CO transition, while an antiferromagnetic (AFM) state coexists with a ferromagnetic (FM) state and a paramagnetic (PM) state at temperatures below the Néel temperature ( T N ).