Boundary Energies and the Geometry of Phase Separation in Double--Exchange Magnets

TL;DR

This paper calculates boundary energies in phase-separated double-exchange magnets, revealing how orientation dependence influences the shape and stability of phase domains, with implications for transport properties near percolation thresholds.

Contribution

It introduces a detailed calculation of boundary energies considering orientation dependence, affecting the understanding of phase geometry in double-exchange magnets.

Findings

Orientation dependence alters droplet shapes in 2D.

Stripe phases can be stabilized by boundary energy effects.

Hysteretic transport properties are expected near percolation threshold.

Abstract

We calculate the energy of a boundary between ferro- and antiferromagnetic regions in a phase separated double-exchange magnet in two and three dimensions. The orientation dependence of this energy can significantly affect the geometry of the phase-separated state in two dimensions, changing the droplet shape and possibly stabilizing a striped arrangement within a certain range of the model parameters. A similar effect, albeit weaker, is also present in three dimensions. As a result, a phase-separated system near the percolation threshold is expected to possess intrinsic hysteretic transport properties, relevant in the context of recent experimental findings.