Spin-wave scattering at low temperatures in manganite films

TL;DR

This study investigates how spin-wave and small-polaron scattering influence low-temperature resistivity in manganite films, revealing spin-wave scattering as a dominant transport mechanism through detailed magnetic field and temperature dependence analysis.

Contribution

It provides a detailed analysis of spin-wave scattering effects on resistivity in manganite films, highlighting its significance at low temperatures.

Findings

Resistivity follows a model combining residual, polaron, and spin-wave scattering terms.

Spin-wave scattering is identified as a key low-temperature transport mechanism.

Differences in metal-insulator transition temperatures are explained by scattering mechanisms.

Abstract

The temperature $T$ and magnetic field $H$ dependence of the resistivity $\rho$ has been measured for La$_{0.8-y}$Sr$_{0.2}$MnO$_{3}$ (y=0 and 0.128) films grown on (100) SrTiO$_{3}$ substrates. The low-temperature $\rho$ in the ferromagnetic metallic region follows well $\rho (H,T)=\rho _{0}(H)+A(H)\omega_{s}/\sinh (\hbar \omega_{s}/2k_{B}T)+B(H)T^{7/2}$ with $\rho _{0}$ being the residual resistivity. We attribute the second and third term to small-polaron and spin-wave scattering, respectively. Our analysis based on these scattering mechanisms also gives the observed difference between the metal-insulator transition temperatures of the films studied. Transport measurements in applied magnetic field further indicate that spin-wave scattering is a key transport mechanism at low temperatures.