Electrical resistivity in the ferromagnetic metallic state of La-Ca-MnO<InlineEquation ID="Equ1"> <EquationSource Format="TEX">$\mathsf{_{3}}$</EquationSource> </InlineEquation>: Role of electron-phonon interaction
The temperature-dependent resistivity of the perovskite manganites La<Subscript>1-x </Subscript>Ca<Subscript> x </Subscript>MnO<Subscript>3</Subscript>, 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 (<InlineEquation ID="Equ2"> <EquationSource Format="TEX">$\omega_{ac})$</EquationSource> </InlineEquation> as well as high-frequency optical phonons (<InlineEquation ID="Equ3"> <EquationSource Format="TEX">$\omega_{op})$</EquationSource> </InlineEquation>, 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. <InlineEquation ID="Equ4"> <EquationSource Format="TEX">$\omega_{ac}$</EquationSource> </InlineEquation> and <InlineEquation ID="Equ5"> <EquationSource Format="TEX">$\omega_{op}$</EquationSource> </InlineEquation>, when subtracted from thin film data, infers a power temperature dependence over most of the temperature range. The quadratic temperature dependence of <InlineEquation ID="Equ6"> <EquationSource Format="TEX">$\rho_{\it diff.}=[ \rho_{\exp} . - \{\rho_{0} + \rho_{e\text{-}ph} (= \rho_{ac} + \rho_{op}) \} ]$</EquationSource> </InlineEquation> is understood in terms of electron-electron scattering. Moreover, in the higher temperature limit, the difference can be varies linearly with T <Superscript>4.5</Superscript> 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. Copyright Springer-Verlag Berlin/Heidelberg 2004
