Possible manifestation of spin fluctuations in the temperature behavior of resistivity in Sm_{1.85}Ce_{0.15}CuO_4 thin films
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A pronounced step-like (kink) behavior in the temperature dependence of resistivity $ρ(T)$ is observed in the optimally-doped $Sm_{1.85}Ce_{0.15}CuO_4$ thin films around $T_{sf}=87K$ and attributed to manifestation of strong spin fluctuations induced by $Sm^{3+}$ moments with the energy $\hbar ω_{sf}=k_BT_{sf}\simeq 7meV$. In addition to fluctuation induced contribution $ρ_{sf}(T)$ due to thermal broadening effects (of the width $ω_{sf}$), the experimental data are found to be well fitted accounting for residual (zero-temperature) $ρ_{res}$, electron-phonon $ρ_{e-ph}(T)=AT$ and electron-electron $ρ_{e-e}(T)=BT^2$ contributions. The best fits produced $ω_p=2.1meV$, $τ_0^{-1}=9.5\times 10^{-14}s^{-1}$, $λ=1.2$, and $E_F=0.2eV$ for estimates of the plasmon frequency, the impurity scattering rate, electron-phonon coupling constant, and the Fermi energy, respectively.
6 pages (REVTEX4), 2 EPS figures; accepted for publication in JETP Letters
6 pages (REVTEX4), 2 EPS figures; accepted for publication in JETP Letters