Effects of Bi3+ doping on the charge ordering and high-field phase diagram of La0.5-Bi Ca0.5MnO3

La _{0.5- x}Bi _xCa _0.5MnO ₃ ( x = 0, 0.05, 0.1 and 0.2) compounds have been prepared to study the effects of Bi ³⁺ substitution on the structure, magnetic and magnetotransport properties. Experimental results show that Bi ³⁺ dopants have induced a distinct lattice distortion and phase separated state in which the long range ferromagnetic order turns into short range ferromagnetic clusters, and the charge ordering/antiferromagnetism and ferromagnetic clusters coexist in the system. Bi ³⁺ doping induced disorders lead to the presence of a Griffith-like phase. The hybridization between Bi ³⁺-6s orbitals and O ^2–-2p orbitals produces a localization of O ^2–-2p electrons and lattice distortion, which plays an important role in favoring charge ordering state and multiple magnetic ordering. The charge ordering antiferromagnetic collapses into ferromagnetic phase through a metamagnetic transition with applying a sufficiently high magnetic field. A T- H_C phase diagram was determined based on the magnetization and electrical transport measurements, in which the phase boundary is figured out.