Long-Ranged Orientational Order in Dipolar Fluids

TL;DR

This paper demonstrates that removing demagnetizing fields restores the shape-independent thermodynamic limit in dipolar fluids, revealing that such fluids can exhibit inhomogeneous magnetization textures due to spontaneous magnetization.

Contribution

It clarifies the role of demagnetizing fields in dipolar fluids, correcting previous claims about shape-dependent thermodynamic behavior and showing the emergence of inhomogeneous magnetization textures.

Findings

Removing demagnetizing fields restores shape-independent thermodynamics.

Spontaneously magnetized liquids can form inhomogeneous magnetization textures.

Previous shape-dependent claims are due to neglecting demagnetizing fields.

Abstract

Recently Groh and Dietrich claimed the thermodynamic state of a dipolar fluid depends on the shape of the fluid's container. For example, a homogeneous fluid in a short fat container would phase separate when transferred to a tall skinny container of identical volume and temperature. Their calculation thus lacks a thermodynamic limit. We show that removal of demagnetizing fields restores the true, shape independent, thermodynamic limit. As a consequence, spontaneously magnetized liquids display inhomogeneous magnetization textures.