Title: Magnetic properties of nanoparticles compacts with controlled broadening of the particle size distribution,
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.