Simulations of Bond Percolation and Synthesis of Bulk Polycrystalline Rare-Earth Nickelates La_1-xR_xNiO₃ (R = Y, Nd, Sm; x = 0-1)

We report high resolution x-ray diffraction, electrical resistivity, AC and DC magnetic susceptibility, measurement on high purity bulk polycrystalline La_1-xR_x NiO₃ (R= Y, Nd, Sm; x= 0–1). Sol-Gel synthesis routes followed by high pressure (200-230 Bar) and high temperature (800-900°C) under an oxygen atmosphere. This carefully controlled approach ensures the maintenance of small particle sizes and enhances the overall purity of the resulting samples. Furthermore, we incorporate bond-percolation simulations that employ theoretical models to reveal that the metal-insulator transition occurs at a (universal) rare-earth concentration of approximately xc = 0.3575...