Thermodynamics of a continuous medium with electric dipoles and magnetic moments

TL;DR

This paper develops a thermodynamic framework for multicomponent fluids with electric and magnetic properties, analyzing how electromagnetic fields influence their behavior and relaxation processes.

Contribution

It introduces a comprehensive formalism that incorporates chemical composition, dissipation, and electromagnetic effects in the thermodynamics of charged fluids with dipoles and magnetic moments.

Findings

Describes dissipation via scalar, vector, and pseudo-vector terms.

Derives relations for Lehmann, Debye, and Landau-Lifshitz effects.

Predicts temperature gradients influence magnetic vortex dynamics.

Abstract

The thermodynamics of an electrically charged, multicomponent fluid with spontaneous electric dipoles and magnetic moments is analysed in the presence of electromagnetic fields. Taking into account the chemical composition of the current densities and stress tensors leads to three types of dissipation terms: scalars, vectors and pseudo-vectors. The scalar terms account for chemical reactivities, the vectorial terms account for transport and the pseudo-vectorial terms account for relaxation. The linear phenomenological relations, derived from the irreversible evolution, describe notably the Lehmann and electric Lehmann effects, the Debye relaxation of polar molecules and the Landau-Lifshitz relaxation of the magnetisation. This formalism accounts for the thermal and electric magnetisation accumulations and magnetisation waves. It also predicts that a temperature gradient affects the dynamics of magnetic vortices and drives magnetisation waves.