Indonesia Conference Directory

Polycrystalline La0.7Sr0.2Ba0.1Mn1-xNixO3 (x = 0.02 and 0.05) has been successfully synthesized by sol-gel method. This research aims to investigate the effects of low nickel substitution on the correlation between structure, microstructure, and electrical transport behavior. From Rietveld refinement result, crystal structure both samples were found to be Rhombohedral with R-3c (167) space group. Low nickel substitution at Mn-site shows that the Mn-O-Mn bond angle decreases and the Mn-O bond length increase which linked Jahn-Teller distortion, double exchange, core-shell model, and percolation model. Scanning electron microscope (SEM) result reveals that nickel substitution leads to smaller grain size. Temperature-dependent resistivity ρ(T) has been measured at 15-285 K with zero field cooling. The ρ(T) increases with decreasing grain size because of the enhancement of the grain boundary effect with the increase in the nickel content. The Curie temperature (TCMod) and the temperature of the metal-insulator transition (TM-I) moves to lower temperatures with increasing nickel substitution content. Percolation model can describe the electrical behavior of both samples based on electron-electron, electron-magnon, and electron-phonon scattering, and Kondo-like spin dependent scattering at low temperature and adiabatic small polaron hopping at high temperature.