Electrical transport analysis of Sr2+ substitution at the Ca-site of divalent-doped La0.5ca0.5-xsrₓMNo₃ (x = 0.00, 0.10, 0.20) manganite using scattering and hopping models

This research explores the effect of Sr2+ ion replacement at the Ca-site in divalent-doped La0.5Ca0.5MnO3 manganites, which are a type of perovskite-structured materials exhibiting fascinating magnetic and electronic transport characteristics. While La0.5Ca0.5-xSrxMnO3 is recognized for its metal-insulator transition and charge-ordering characteristics, a detailed comprehension of the impact of different Sr²⁺ doping concentrations (x = 0.00, 0.10, 0.20) on electrical resistivity remains limited. The objectives of this research are to synthesize La0.5Ca0.5-xSrxMnO3 samples via the solid-state method and to evaluate their temperature-dependent electrical transport properties using scattering and small polaron hopping (SPH) models. All synthesized samples were characterized via resistivity measurements taken over a temperature range of 30–300 K under zero magnetic fields (0 T) and with a magnetic field of 0.8 T. The metals region (T < TMI) best fit a combination scattering model (ρ = ρ0+ ρ2.5T2.5), with clear trends of decreasing residual resistivity (ρ0) and scattering coefficient (ρ2.5) as Sr content increased which is indicative of enhanced conduction and higher connectivity between various grains. The insulating region (T > TMI) best matched the SPH model of carrier transport with activation energy (Ea) showing the consistent decrease away from zero as compared to the structural disorder caused by the Sr²⁺ substitution and thus, further confirming better carrier mobility. Overall, these findings shows that Sr²⁺ doping not only reduces structural disorder and lattice distortion but also significantly enhances electrical transport, thus offering a promising route for optimizing manganites in next-generation electronic and spintronic applications.