Observation of excess resistance anomaly at resistive transitions in Ag/Au nanostructures

TL;DR

This study reports an unusual resistance peak at the resistive transition in Ag/Au nanostructures, which varies with device configuration and can be partially suppressed by magnetic fields, suggesting complex underlying physical mechanisms.

Contribution

It presents the first observation of excess resistance anomalies in Ag/Au nanostructures and explores possible physical explanations involving phase slip centers.

Findings

Excess resistance peaks up to 300% above normal state

Observed in about 10% of devices between 10-100 K

Magnetic field of 9 T partially suppresses the excess resistance

Abstract

The resistive transition in nanocomposite films of silver (Ag) nanoclusters of ~ 1 nm diameter embedded in gold (Au) matrix exhibits an anomalous resistance peak at the onset of the transition, even for transition temperatures as high as 260 K. The maximum value of the resistance ranges between ~ 30% - 300% above that of the normal state depending on devices as well as lead configuration within a single device. The excess resistance regime was observed in about 10% of the devices, and extends from ~ 10 - 100 K. Application of magnetic field of 9 T was found to partially suppress the excess resistance. From the critical current behavior, as well as negative differential resistance in the current-voltage characteristics, we discuss the possibility of interacting phase slip centers and alternate physical scenarios that may cause the excess resistance in our system.