Interpretation of Temperature-Dependent Resistivity of La–Pb–MnO₃: Role of Electron–Phonon Interaction

Abstract

The present paper deals with the theoretical investigation of temperature-dependent resistivity of the perovskite manganites La_0.78Pb_0.22MnO_3-δ within the framework of the classical electron–phonon model of resistivity, i.e., the Bloch–Gruneisen model. Due to inherent acoustic (low-frequency) phonons (ω _ac ) as well as high-frequency optical phonons (ω _op ), the contributions to the electron–phonon resistivity have first been estimated. At low temperatures the acoustic phonons of the oxygen-breathing mode yield a relatively larger contribution to the resistivity as compared to the contribution of optical phonons. Furthermore, the nature of phonons changes around T = 215 K exhibiting a crossover from an acoustic to optical phonon regime with elevated temperature. The contribution to resistivity estimated by considering both phonons, i.e., ω _ac and ω _op , when subtracted from experimental data, infers a T^4.5 temperature dependence over most of the temperature range. Deduced T^4.5 temperature dependence of ρ_diff = [ρ_exp − {ρ₀ + ρ_e-ph( = ρ_ac + ρ_op)}] is justified in terms of electron–magnon scattering within the double exchange (DE) process. Within the proposed scheme, the present numerical analysis of temperature dependent resistivity shows similar results as those revealed by experiments