Phenomenological model of anomalous magnon softening and damping in half-metallic manganites

TL;DR

This paper introduces a phenomenological two-fluid model to explain anomalous magnon softening and damping in half-metallic manganites, combining ferromagnetic Fermi-liquid and non-Fermi-liquid components to account for experimental observations.

Contribution

It presents a novel two-fluid phenomenological model that captures the complex magnon behavior in manganites, integrating Fermi-liquid and non-Fermi-liquid interactions.

Findings

Explains zone-boundary magnon softening and damping.

Shows coupling effects lead to long wavelength magnon damping.

Accounts for zero-point effects and Landau damping.

Abstract

To describe anomalous zone-boundary softening and damping of magnons in manganites we present a phenomenological two-fluid model containing ferromagnetic Fermi-liquid and non-Fermi-liquid components. The Fermi-liquid component accounts for softening of zone-boundary magnons and for the Landau damping of magnons in the Stoner continuum arising at low frequencies due to zero-point effects. Coupling of the Fermi-liquid and non-Fermi-liquid fluids yields conventional long wavelength magnons damped due to their coupling with longitudinal spin fluctuations.