Spin Excitation Spectrum of La$_{1-x}A_x$MnO$_3$

TL;DR

This paper investigates the spin excitation spectrum of La$_{1-x}A_x$MnO$_3$ using the double-exchange model and spin wave approximation, successfully reproducing experimental neutron scattering data and estimating key electronic parameters.

Contribution

It provides a theoretical analysis of the spin excitation spectrum in manganates, matching experimental results and estimating electronic interaction parameters.

Findings

Reproduces neutron scattering spin wave dispersion

Estimates electron bandwidth and Hund's coupling

Validates the double-exchange model for manganates

Abstract

As an effective model to describe perovskite-type manganates (La,$A$)MnO$_3$, the double-exchange model on a cubic lattice is investigated. Spin excitation spectrum of the model in the ground state is studied using the spin wave approximation. Spin wave dispersion relation observed in the inelastic neutron scattering experiment of La$_{0.7}$Pb$_{0.3}$MnO$_3$ is reproduced. Effective values for the electron bandwidth as well as Hund's coupling is estimated from the data.