A versatile cryo-transfer system, connecting cryogenic focused ion beam sample preparation to atom probe microscopy.

Leigh T Stephenson,Chandra Macauley,Alexander Rausch,Martina Heller,Peter Felfer,Frank Kümmel

doi:10.1371/journal.pone.0245555

Leigh T Stephenson, Chandra Macauley + Show 4 more

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https://doi.org/10.1371/journal.pone.0245555

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Journal: PloS one	Publication Date: Jan 19, 2021
Citations: 14	License type: CC BY 4.0

Affiliation: University of Erlangen-Nuremberg

Abstract

Atom probe tomography (APT) is a powerful technique to obtain 3D chemical and structural information, however the 'standard' atom probe experimental workflow involves transfer of specimens at ambient conditions. The ability to transfer air- or thermally-sensitive samples between instruments while maintaining environmental control is critical to prevent chemical or morphological changes prior to analysis for a variety of interesting sample materials. In this article, we describe a versatile transfer system that enables cryogenic- or room-temperature transfer of specimens in vacuum or atmospheric conditions between sample preparation stations, a focused ion beam system (Zeiss Crossbeam 540) and a widely used commercial atom probe system (CAMECA LEAP 4000X HR). As an example for the use of this transfer system, we present atom probe data of gallium- (Ga)-free grain boundaries in an aluminum (Al) alloy specimen prepared with a Ga-based FIB.

Highlights

Cryogenic sample preparation and characterization has been developed and widely used in the biology community since the 1970s [1] and is only recently being applied more broadly to materials science
We describe a custom-built versatile transfer system that enables transfer of samples that are sensitive to air or thermal exposure between sample preparation stations such as a FIB/scanning electron microscopes (SEMs) and a local electrode atom probe (LEAP)
After preparing the sharpened atom probe sample in the FIB at -140 ̊C (133 K), the cryogenicand environmental-transfer system was used to transfer the sample to the LEAP while maintaining a measured temperature of -160 ̊C in the actively cooled transfer device (ACTD)

Summary

Introduction

Cryogenic sample preparation and characterization has been developed and widely used in the biology community since the 1970s [1] and is only recently being applied more broadly to materials science These techniques open up a wide range of materials, including soft materials and environmentally unstable materials, that can be studied e.g. in electron microscopes such as transmission electron microscopes (TEMs) [2, 3] and scanning electron microscopes (SEMs) [4, 5].

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