Demagnetization factor for a powder of randomly packed spherical particles

TL;DR

This study numerically calculates the demagnetization factors of randomly packed spherical powders, revealing how porosity, aspect ratio, and permeability influence magnetic properties.

Contribution

It introduces a numerical model to compute demagnetization factors for various powder packings, considering different particle size distributions and permeabilities.

Findings

Demagnetization factor is close to theoretical value at permeability 2.

Normalized standard deviation of magnetization is around 6-7%.

Demagnetization factor decreases with increasing permeability.

Abstract

The demagnetization factors for randomly packed spherical particle powders with different porosities, sample aspect ratios and monodisperse, normal and log-normal particle size distributions have been calculated using a numerical model. For a relative permeability of 2, comparable to room temperature Gd, the calculated demagnetization factor is close to the theoretical value. The normalized standard deviation of the magnetization in the powder was 6.0%-6.7%. The demagnetization factor decreased significantly, while the standard deviation of the magnetization increased, for increasing relative permeability.