The Exchange Parameters in Lanthanum Manganites

TL;DR

This paper investigates the spin-wave spectrum in metallic ferromagnetic lanthanum manganites, analyzing exchange interactions to determine parameters using neutron scattering data, enhancing understanding of magnetic properties in these materials.

Contribution

It provides a detailed analysis of exchange parameters in lanthanum manganites considering multiple interaction spheres and compares theoretical spectra with experimental data.

Findings

Exchange parameters for La0.75Ca0.25MnO3 and La0.70Ca0.30MnO3 were numerically evaluated.

Magnon spectra enable dispersion relation analysis along various crystallographic directions.

The study incorporates superexchange and double exchange interactions in the modeling.

Abstract

The spin-wave spectrum in the metallic ferromagnetic lantha-num cubic manganites was investigated. The interactions with four coordination spheres (32 neighbors) were taken into ac-count. The Heisenberg superexchange between all manganese ions as well as double exchange between the manganese ions with different valence were under consideration. The obtained magnon spectrum permits to investigate dispersion relations along an any crystallographic directions. This possibility was used for the numerical evaluation of the exchange parameters in the compounds La0.75Ca0.25MnO3 and La0.70Ca0.30MnO3 from the inelastic neutron scattering data.