Scaling Analysis and Application: Phase Diagram of Magnetic Nanorings and Elliptical Nanoparticles

TL;DR

This paper investigates the magnetic phase diagrams of nanorings and elliptical nanoparticles using a universal scaling approach, revealing how geometry influences magnetic states like vortex and ferromagnetic configurations.

Contribution

It introduces a universal scaling method applicable to various nanoparticle shapes and provides detailed phase diagrams including the effects of vortex cores and elliptical geometries.

Findings

Phase diagrams depend on nanoparticle geometry and size.

Triple points in phase diagrams relate linearly to inner radius.

Double vortex states are stable in specific elliptical regions.

Abstract

The magnetic properties of single-domain nanoparticles with different geometric shapes, crystalline anisotropies and lattice structures are investigated. A recently proposed scaling approach is shown to be universal and in agreement with dimensional analysis coupled with an assumption of {\em incomplete} self-similarity. It is used to obtain phase diagrams of magnetic nanoparticles featuring three competing configurations: in-plane and out-of-plane ferromagnetism and vortex formation. The influence of the vortex core on the scaling behavior and phase diagram is analyzed. Three-dimensional phase diagrams are obtained for cylindrical nanorings, depending on their height, outer and inner radius. The triple points in these phase diagrams are shown to be in linear relationship with the inner radius of the ring. Elliptically shaped magnetic nanoparticles are also studied. A new parametrization for double vortex configurations is proposed, and regions in the phase diagram are identified where the double vortex is a stable ground state.