Effect of B-site bismuth doping on magnetic and transport properties of La_0.5Ca_0.5Mn_1−xBi_xO₃ thin films

The magnetic properties of manganites are extremely sensitive to the doping-induced structural (e.g., crystal structure, site occupancy and chemical ordering) modulations. Here, we report the effect of B-site bismuth doping on the magnetic and transport properties in La_0.5Ca_0.5Mn_1−xBi_xO₃ (LCMBO) thin films (for x = 0, 0.02 and 0.05) for high-efficiency spintronics devices. For thin film of LCMBO (with x = 0.02), a significant increase in the magnetization and ferromagnetic ordering temperature (T_C) is observed. Also, about 98% magnetoresistance (MR) and unusually large (~ 42%) anisotropic magnetoresistance (AMR) are observed at 50 K in the same LCMBO (for x = 0.02) thin film. This observed improvement in T_C, MR and AMR in LCMBO (with x = 0.02) thin film may be attributed to the modulation of the trapped electrons through JT distortions due to the replacement of Mn³⁺ ions by larger Bi³⁺ ions. With a further increase in bismuth doping (for x = 0.05) at the B-site, a significant decrease in magnetization and T_C has been observed.