Electrical resistivity in the ferromagnetic metallic state of La-Ca-MnO3: Role of electron-phonon interaction
School of Physics, Vigyan Bhawan, Devi Ahilya University, Khandwa Road
Campus, Indore 452017, India
Revised: 8 April 2004
Published online: 12 August 2004
The temperature-dependent resistivity of the perovskite manganites LaCaxMnO3, with x = 0.33, is theoretically analysed within the framework of the classical electron-phonon model of resistivity, i.e., the Bloch-Gruneisen model. Due to inherent acoustic (low-frequency) phonons ( as well as high-frequency optical phonons (, the contributions to the resistivity have first been estimated. The acoustic phonons of the oxygen-breathing mode yield a relatively larger contribution to the resistivity compared to the contribution of optical phonons. Furthermore, the nature of phonons changes around T = 167 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. and , when subtracted from thin film data, infers a power temperature dependence over most of the temperature range. The quadratic temperature dependence of is understood in terms of electron-electron scattering. Moreover, in the higher temperature limit, the difference can be varies linearly with T4.5 in accordance with the electron-magnon scattering in the double exchange process. Within the proposed scheme, the present numerical analysis of temperature dependent resistivity shows similar results as those revealed by experiment.
PACS: 5.47.Gk – Colossal magnetoresistance / 72.15.-v – Electronic conduction in metals and alloys / 74.25.Kc – Phonons / 75.30.Ds – Spin waves
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2004