Magnonic Crystal Theory of the Spin-Wave Frequency Gap in Low-Doped $La_{1-x}Ca_{x}MnO_{3}$ Manganites

TL;DR

This paper develops a 3D magnonic crystal theory to explain the spin-wave frequency gap observed in low-doped La-Ca manganites, suggesting these manganites may naturally behave as 3D magnonic crystals.

Contribution

It introduces a theoretical model of 3D magnonic crystals applied to manganites, linking experimental spin-wave gaps to magnonic crystal properties.

Findings

The theory successfully explains the observed spin-wave gap.

Certain manganites can be considered as natural 3D magnonic crystals.

Abstract

A theory of three-dimensional (3D) hypothetical magnonic crystal (conceived as the magnetic counterpart of the well-known photonic crystal) is developed and applied to explain the existence of a spin-wave frequency gap recently revealed in low-doped manganites $La_{1-x}Ca_{x}MnO_{3}$ by neutron scattering. A successful confrontation with the experimental results allows us to formulate a working hypothesis that certain manganites could be regarded as 3D magnonic crystals existing in nature.