Strong resistance nonlinearity and third harmonic generation in the unipolar resistance switching of NiO thin films

TL;DR

This study explores third harmonic generation in NiO thin films with unipolar resistance switching, revealing strong nonlinear behavior linked to Joule heating and filament connectivity changes, which could inform future electronic device designs.

Contribution

It demonstrates the relationship between resistance states and third harmonic response in NiO films, highlighting filament connectivity changes during switching.

Findings

Resistance variations up to 60% in low resistance states.

Third harmonic coefficient B3f proportional to R^{2+w} with w ≈ 2.07.

Filament connectivity changes resemble classical percolating systems.

Abstract

We investigated third harmonic generation in NiO thin films, which exhibit unipolar resistance switching behavior. We found that the low resistance states of the films were strongly nonlinear, with variations in the resistance R as large as 60%. This strong nonlinear behavior was most likely caused by Joule heating of conducting filaments inside the films. By carefully controlling the applied dc bias, we obtained several low resistance states, whose values of the third harmonic coefficient B3f were proportional to R2+w (with w = 2.07). This suggested that the resistance changes of the NiO films were accompanied by connectivity changes of the conducting filaments, as observed in classical percolating systems.