A-site cationic disorder induced significantly large magnetoresistance in polycrystalline La_0.2Gd_0.5Ba_0.3MnO₃ compound

Highlights: •Large magnetoresistance observed in La_0.2Gd_0.5Ba_0.3MnO₃ compound. •Results analyzed considering disorder induced short range interaction. •Size disorder plays vital role for colossal magnetoresistance. - Abstract: The observation of significantly large magnetoresistance at the liquid nitrogen temperature range in the polycrystalline La_0.2Gd_0.5Ba_0.3MnO₃ (LGBMO) compound has been addressed in the present manuscript. The motivation of considering LGBMO sample is the average 'A' site ionic radius $〈r_A〉$ and tolerance factor (t), almost same as that of La_0.7Sr_0.3MnO₃ (LSMO), which is a well studied colossal magnetoresistive material. Magnetoresistance of the LGBMO compound has been compared with the LSMO as well as parent compound La_0.7Ba_0.3MnO₃(LBMO) to show the enhancement of magnetoresistance in LGBMO compound. This observed nature has been elucidated considering the disorder induced short range magnetic interaction due to the enhance size disorder parameter (${\sigma }^2$). Our study revels that, size disorder parameter plays the crucial role for enhancing the colossal magnetoresistance.