Resonance Damping in Ferromagnets and Ferroelectrics

TL;DR

This paper explores the analogous relaxation mechanisms in ferromagnets and ferroelectrics, highlighting how viscous sound wave damping via magnetostriction and electrostriction govern their relaxation dynamics.

Contribution

It develops a unified phenomenological framework for relaxation in magnetized and polarized crystals, extending Gilbert's and Khalatnikov's equations to include damping via sound wave viscosity.

Findings

Relaxation times are linked to viscous damping of sound waves.

Magnetostriction and electrostriction are key damping mechanisms.

Unified equations describe relaxation in both ferromagnets and ferroelectrics.

Abstract

The phenomenological equations of motion for the relaxation of ordered phases of magnetized and polarized crystal phases can be developed in close analogy with one another. For the case of magnetized systems, the driving magnetic field intensity toward relaxation was developed by Gilbert. For the case of polarized systems, the driving electric field intensity toward relaxation was developed by Khalatnikov. The transport times for relaxation into thermal equilibrium can be attributed to viscous sound wave damping via magnetostriction for the magnetic case and electrostriction for the polarization case.