Increase in the magnitude of the energy barrier distribution in Ni nanoparticles due to dipolar interactions

TL;DR

This study investigates how dipolar interactions among Ni nanoparticles increase the energy barrier distribution, affecting magnetic properties relevant for data storage quality control.

Contribution

It demonstrates that dipolar interactions significantly increase the mean energy barrier in Ni nanoparticle systems, providing a new approach for quality assessment.

Findings

Mean energy barrier <E_b> increases with nanoparticle concentration

Scaling of ac susceptibility remains valid across samples

Dipolar interactions influence magnetic stability

Abstract

The energy barrier distribution Eb of five samples with different concentrations x of Ni nanoparticles using scaling plots from ac magnetic susceptibility data has been determined. The scaling of the imaginary part of the susceptibility Chi"(nu, T) vs. Tln(t/tau_0) remains valid for all samples, which display Ni nanoparticles with similar shape and size. The mean value <E_b> increases appreciably with increasing x, or more appropriately with increasing dipolar interactions between Ni nanoparticles. We argue that such an increase in <Eb> constitutes a powerful tool for quality control in magnetic recording media technology where the dipolar interaction plays an important role.