# The demagnetization factor for randomly packed spheroidal particles

## TL;DR

This study examines how the shape of spheroidal particles in a magnetic powder influences the demagnetization factor and internal magnetization variation, revealing dependence on particle aspect ratio and packing structure.

## Contribution

It introduces numerical models to analyze the impact of particle aspect ratio on demagnetization factors in randomly packed spheroidal powders, highlighting shape-dependent packing effects.

## Key findings

- Demagnetization factor depends on particle aspect ratio due to packing, not direct magnetic interaction.
- Magnetization variation across powder ranges from 3% to 8%, increasing with shape deviation from sphere.
- Within-particle magnetization variation remains around 5% regardless of shape.

## Abstract

We investigate if the demagnetization factor for a randomly packed powder of magnetic spheroidal particles depend on the shape of the spheroidal particles and what the internal variation in magnetization is within such a powder. A spheroid is an ellipsoid of revolution, i.e. an ellipsoid with two semi-major axis being equal. The demagnetization factor is calculated as function of particle aspect ratio using two independent numerical models for several different packings, and assuming a relative permeability of 2. The calculated demagnetization factor is shown to depend on particle aspect ratio, not because of direct magnetic interaction but because the particle packing depend on the aspect ratio of the particles. The relative standard deviation of the magnetization across the powder was 3\%-8\%, increasing as the particle shape deviates from spherical, while the relative standard deviation within each particle was relatively constant around 5\%.