Analysis of Low Temperature Resistivity in the Ferromagnetic Metallic State of Pb‐Doped Manganites

The temperature‐dependent resistivity of the perovskite manganites La0.78Pb0.22MnO3−δ is theoretically analyzed within the framework of the Bloch‐Gruneisen (BG) model. Due to inherent acoustic low‐frequency phonons as well as high‐frequency optical phonons, 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 as compared to that of optical phonons. Furthermore, the nature of phonons changes around T = 215 K and a crossover from a acoustic phonons regime to a optical phonons with elevated temperature. The contribution to resistivity estimated by considering both phonons, when subtracted from experimental data, infers a T4.5 temperature dependence over most of the temperature range and understood in terms of electron‐magnon scattering within the double exchange process.