# Magnetic properties of nanoparticles compacts with controlled broadening of the particle size distribution

## TL;DR

This study explores how controlled broadening of particle size distribution in maghemite nanoparticle assemblies affects their magnetic properties, revealing linear relationships between particle size composition and superspin glass transition temperatures.

## Contribution

It demonstrates that broadening the size distribution in magnetic nanoparticle compacts does not hinder the observation of well-defined superspin glass transitions, with transition temperatures scaling linearly with particle size proportion.

## Key findings

- Superspin glass transition temperatures increase linearly with larger particle fraction.
- Broadening size distribution does not obscure magnetic transition signatures.
- Uniform nanoparticles can be used to study effects of size distribution on magnetism.

## Abstract

Binary random compacts with different proportions of small (volume V) and large (volume 2V) bare maghemite nanoparticles (NPs) are used to investigate the effect of controllably broadening the particle size distribution on the magnetic properties of magnetic NP assemblies with strong dipolar interaction. A series of eight random mixtures of highly uniform 9.0 and 11.5 nm diameter maghemite particles prepared by thermal decomposition are studied. In spite of severely broadened size distributions in the mixed samples, well defined superspin glass transition temperatures are observed across the series, their values increasing linearly with the weight fraction of large particles.