Unusual non-equilibrium behavior of cupric oxide nanoparticles

TL;DR

This study investigates the unique magnetic behavior of cupric oxide nanoparticles, revealing atypical non-equilibrium phenomena that differ from conventional antiferromagnetic nanoparticle systems.

Contribution

It provides the first detailed analysis of the unusual magnetic properties of CuO nanoparticles, highlighting their non-superparamagnetic and non-spin glass-like nature.

Findings

FC and ZFC bifurcate above Neel temperature

Absence of the typical ZFC peak

No memory effects observed

Abstract

We report studies on temperature, field and time dependence of magnetization on cupric oxide nanoparticles of sizes 9 nm, 13 nm and 16 nm. The nanoparticles show unusual features in comparison to other antiferromagnetic nanoparticle systems. The field cooled (FC) and zero field cooled (ZFC) magnetization curves bifurcate well above the Neel temperature and the usual peak in the ZFC magnetization curve is absent. The system does not show any memory effects which is in sharp contrast to the usual behavior shown by other antiferromagnetic nanoparticles. It turns out that the nature of CuO nanoparticles is very strange and is neither superparamagnetic nor spin glass-like .