Computational approach to finite size and shape effects in iron nanomagnets

TL;DR

This paper presents a computational method combining spin wave approximation and first principles calculations to analyze finite size and shape effects in iron nanomagnets across a wide size range, enabling high throughput studies.

Contribution

It introduces a scalable computational approach that links first principles parameters to spin wave models for nanomagnets, allowing analysis of large systems beyond traditional DFT capabilities.

Findings

Magnetization depends on size, shape, and temperature.

Method validated for nanomagnets from hundreds to tens of millions of atoms.

Enables high throughput analysis of nanomagnetic materials.

Abstract

We develop and validate a computational approach to nanomagnets. It is built on the spin wave approximation to a Heisenberg ferromagnet whose parameters can be calculated from a first principles theory (e.g. density functional theory). The method can be used for high throughput analysis of a variety of nanomagnetic materials. We compute the dependence of the magnetization of an iron nanomagnet on temperature, size and shape. The approach is applied to nanomagnets in the range of 432 atoms to 59 million atoms, a size which is several orders of magnitude beyond the scalability of density functional theory.