The influence of Ga$^+$-irradiation on the transport properties of mesoscopic conducting thin films

TL;DR

This study investigates how 30keV Ga$^+$ ion irradiation affects the electrical transport properties of various thin films, revealing significant changes at low fluences that impact FIB applications and proposing protective methods.

Contribution

It provides new insights into the effects of Ga$^+$ irradiation on thin film transport properties and introduces a method for protecting samples during irradiation.

Findings

Transport properties change significantly at low Ga$^+$ fluences

Irradiation effects occur below typical patterning fluences

Proposed method for sample protection and selective modification

Abstract

We studied the influence of 30keV Ga$^+$-ions -- commonly used in focused ion beam (FIB) devices -- on the transport properties of thin crystalline graphite flake, La$_{0.7}$Ca$_{0.3}$MnO$_3$ and Co thin films. The changes of the electrical resistance were measured in-situ during irradiation and also the temperature and magnetic field dependence before and after irradiation. Our results show that the transport properties of these materials strongly change at Ga$^+$ fluences much below those used for patterning and ion beam induced deposition (IBID), limiting seriously the use of FIB when the intrinsic properties of the materials of interest are of importance. We present a method that can be used to protect the sample as well as to produce selectively irradiation-induced changes.