Near-field induction heating of metallic nanoparticles due to infrared magnetic dipole contribution

TL;DR

This paper demonstrates that magnetic dipole contributions dominate near-field heat transfer between metallic nanoparticles and substrates at infrared frequencies, highlighting the importance of magnetic effects in nanoscale thermal processes.

Contribution

It reveals that magnetic polarizability surpasses electric polarizability at infrared frequencies, altering the understanding of near-field heat transfer mechanisms for metallic nanoparticles.

Findings

Magnetic polarizability exceeds electric at infrared frequencies.

Magnetic contribution dominates local density of states in near field.

Power absorption is primarily due to eddy current dissipation.

Abstract

We revisit the electromagnetic heat transfer between a metallic nanoparticle and a metallic semi-infinite substrate, commonly studied using the electric dipole approximation. For infrared and microwave frequencies, we find that the magnetic polarizability of the particle is larger than the electric one. We also find that the local density of states in the near field is dominated by the magnetic contribution. As a consequence, the power absorbed by the particle in the near field is due to dissipation by fluctuating eddy currents. These results show that a number of near-field effects involving metallic particles should be affected by the fluctuating magnetic fields.