No abstract

In the field of high-temperature superconductors, atom probe tomography is a relatively new instrument, with the ability to provide a new perspective on the 3D nanoscale microstructure. However, field evaporation of nonmetallic materials is fraught with unique challenges that matter little in the world of metallic evaporation. In this study, we review the laser absorption, correlated evaporation, molecular dissociation, and the crystallographic effects on the field evaporation of 800-m ${\rm RB}{\rm a}_ 2{\rm C}{\rm u}_ 3{\rm O}_{ 7-{\rm \delta }}$ (R = Gd, Sm) coated conductor tapes deposited by Reactive Co-Evaporation Cyclic Deposition and Reaction (RCE-CDR). Ultraviolet 355 nm laser pulsing was found to have a substantial beneficial effect on minimizing the fracture probability compared with 532 nm illumination, especially when evaporating insulating oxide precipitates. This, in turn, allows for the 3D compositional analysis of defects such as flux pinning centers introduced by precipitation and doping. As a result, evidence for the precipitation of nanoscale ${\rm G}{\rm d}_ 2{\rm C}{\rm u}_ 2{\rm O}_ 5$ is discussed. The effect of crystallographic orientation is studied, where [001] aligned evaporation is found to develop compositional aberrations.

As microstructures are increasingly engineered with nanoscale precision, comparably precise metrological tools like Atom Probe Tomography (APT) are crucial for experimental validation. APT has the unique capability of 3D imaging and compositional/isotopic analysis at the subnanometer scale (Gault et al., 2021). However, the informative potential of APT is hindered by nebulous, material-dependent evaporation physics, naturally complex data analysis/visualization, and the standards/specifications set by vendors. Transparent and accessible data analysis tools are critical for reproducible analysis of APT experiments. APAV seeks to bridge the gap of openly accessible analysis tools available to scientists leveraging APT in their research.