Collapse of charge ordering in Bi0.5Sr0.5MnO3 by cation disorder: a magnetic and structural investigation

The structure, transport, and magnetic properties of LaxBi0.5-xSr0.5MnO3 (LBSMO) (x=0.1 and 0.4) were studied through X-ray diffraction, magnetization, and electron spin resonance (ESR) measurements. The structural analysis showed that the LBSMO crystallized in an orthorhombic perovskite structure with Pbnm space group for x=0.1 and Imma space group for x=0.4 and the highly polarizable 6s2 lone pair of Bi3+ was the tuning factor for the structural variations. Magnetic studies revealed that the replacement of Bi ions by La ions resulted in the collapse high temperature charge ordering state of BSMO and it order Ferro Magnetically (FM) with TC around 355 and 330 K for x=0.1 and 0.4, respectively. Both ESR, temperature and field dependant magnetization suggested that there was a coexistence of FM and the paramagnetic phases well below TC and the FM and CO-AFM phases below 250 K of LBSMO.