Spatially resolved materials property tuning using GFIS and LMAIS based FIBs

Introduction
Gas Field Ion Source (GFIS) based Helium Ion Microscopy (HIM) is providing best resolu-
tion Nobel gas focused ion beam (FIB) based imaging and nanofabrication capabilities [1,2].
Liquid Metal Alloy Ion Source (LMAIS) based FIBs, on the other hand enable the nanoscale
modification of the morphology and the elemental composition of materials [3]. Both meth-
ods allow going beyond classical Ga-FIB based material removal.
Description of the Work or Project
I will address in particular low ion fluence modification of materials properties with only
negligible material removal. Examples will include the modification of magnetic, supercon-
ducting, electrical and optical properties in metals, semiconductors and 2D materials. I will
show how the HIM can be used to create arbitrary shaped nano-magnets [4] and tailor their
magnetic properties, with minimal morphological modifications. We use a set of in-situ
probes to follow the change of the magnetic properties during irradiation to allow optimized
fluence delivery [5]. Similarly, we can use the probes to characterize transistors build from
2D materials and follow the change of their electrical properties during ion beam irradiation.
A more fundamental investigation, based on focussed He irradiation of tin spheres, looks at
the importance of interstitial formation and diffusion. However, also beams of other elements
are useful for creating new functionality on the nanometer scale. I will present very recent re-
sults on the application of Dy and Co LMAIS FIB to tune the spin transport properties of
magnetic materials.
Conclusions
Beyond Ga-FIB instruments such as HIM and LMAIS-FIB offer an unprecedented flexibility
for research and development applications. Using in-situ and in-operando techniques further
accelerates the throughput and versatility of FIB based materials research.
Part of this work has been performed in the framework of COST Action FIT4NANO
(CA19140) and the BMBF projects ZF4330905AB9 and ZF4330902DF7.