Charge order and phase separation in Bi0.5Ca0.5Mn1-xCoxO3 system

Polycrystalline Bi0.5Ca0.5Mn1-xCoxO3 (0 <= x <= 0. 12) samples are synthesized by using the solid-state reaction. The effects of Co-doping on charge order of Bi0.5Ca0.5MnO3 are studied. The results show that Co doping leads to the melting of the charge order and the enhancement of the ferromagnetic correlation. For x >= 0. 08, the charge order transition is completely suppressed; however, there are still remaining antiferromagnetic domains inside the system. The phase separation or the coexistence of the charge order and ferromagnetic phase induced by Co-doping plays an important role in the low temperature properties for the system. Moreover, unlike in the case of rare-earth manganites, Co is more efficient to suppress charge order of Bi0.5Ca0.5MnO3 than Cr.