Characterization of Materials through High Resolution Coherent Imaging: Algorithms for High Resolution Coherent Imaging of Materials
Sponsored by: TMS Extraction and Processing Division, TMS Structural Materials Division, TMS: Advanced Characterization, Testing, and Simulation Committee, TMS: Materials Characterization Committee
Program Organizers: Richard Sandberg, Brigham Young University; Ross Harder, Argonne National Laboratory; Xianghui Xiao, Brookhaven National Laboratory; Brian Abbey, La Trobe University; Saryu Fensin, Los Alamos National Laboratory; Ana Diaz, Paul Scherrer Institute; Mathew Cherukara, Argonne National Laboratory
Monday 2:00 PM
March 20, 2023
Room: Aqua 310A
Location: Hilton
Session Chair: Ross Harder, Advanced Photon Source, Argonne National Laboratory
2:00 PM Invited
3D Nanoscale Crystalline Microscopy: The Interest of 3D Bragg Ptychography for Material Science: Virginie Chamard1; 1Institut Fresnel
The design of new materials rely on the knowledge of the structure/property relationship, which often originates from the material sub-micrometric scale structure. Crystalline materials are of major importance in this field, with applications from microelectronics and energy, to biomimetism. Material science calls for imaging approaches able at describing complex crystalline materials at the nanoscale, in 3D, further combining in situ/operando compatibility and high spatial resolution. In this context, the advents of x-ray Bragg ptychography have opened promising perspectives filling the gap between direct microscopies (AFM, SEM, TEM) and x-ray Bragg diffraction analysis. Here, the interest of Bragg ptychography will be illustrated by a series of applications, including detailed characterization of stacking faults in a quantum nanowire, impact of ionic implantation in a polycrystalline metallic material, comparison of different crystallisation mechanisms in calcareous bio-inspired films and 3D imaging of crystalline properties in mollusk shell biominerals.
2:30 PM
Using Automatic Differentiation to Solve the Phase Problem in X-ray Bragg Ptychography: Tao Zhou1; Mathew Cherukara1; Stephan Hruszkewyzcz1; Saugat kandel1; Martin Holt1; 1Argonne National Laboratory
Here we describe the forward propagation in Bragg ptychography using the Takagi-Taupin Equations (TTE). We show that, when combined with Automatic Differentiation (AD), TTE can be used as a general formalism for 3D phase retrieval, applicable to both Bragg ptychography and Bragg Coherent Diffraction Imaging. Compared to conventional Fourier Transform based methods, our approach accounts for additionally refraction, absorption, interference, dynamical effects, and is applicable to any kind of weakly strained material system.
2:50 PM
Near Atomic Resolution BCDI through Materials Modeling: Jason Meziere1; Ross Harder2; Anastasios Pateras3; Richard Sandberg1; 1Brigham Young University; 2Argonne National Laboratory; 3Deutsches Elektronen-Synchrotron DESY
When multi-bend achromat lattice upgrades to synchrotrons are completed (such as the Advanced Photon Source upgrade), it will be feasible to sample a much larger region of reciprocal space than ever before. This extra information may enable imaging of strain through Bragg coherent diffraction imaging (BCDI) at near atomic resolution. This work presents an algorithm using molecular dynamics (MD) and minimization techniques to recover atom positions from coherent x-ray diffraction patterns. MD simulations are used to create realistic grains that would occur experimentally in LAMMPS. From this, a diffraction pattern is simulated in Pynx. The algorithm can then reconstruct the given object from only the diffraction pattern.
3:10 PM
The Application of Advanced Coherent Imaging Technique and Element Analysis on a Self-organized Loop Structure: Yao Li1; Arunodaya Bhattacharya2; Yajie Zhao1; Jean Henry3; Steven Zinkle1; 1University Of Tennessee Knoxville; 2Oak Ridge National Laboratory; 3Commissariat à l'Energie Atomique
After self-ion irradiation at 450 °C, a complex loop structure was observed in BCC Fe-Cr alloys. At low damage (0.35 displacements per atom, dpa), large <001>{200} petal-shaped interstitial dislocation loops were created. For a given branch of a petal-shaped loop, it might have smaller and self-similar branches. Using atomic-resolution STEM-HAADF imaging techniques, we revealed that each petal-shaped loop is a 3-D structure consisting of multiple small <001> sections on different atomic planes with the same plane normal. STEM-EDS imaging under two equivalent two-beam approximations showed distinct Cr segregation on the same petal-shaped loop. To confirm the Cr segregation, atomic-resolution STEM-EDS and APT were applied. The strain field by the complex structure as determined by 4-D STEM techniques will be summarized. At the high damage (3.5dpa), 2-D dislocation loop walls were observed. The formation of 2-D loop walls might be due to the decomposition of petal-shaped loops.
3:30 PM Break
3:50 PM
Fluctuation Analysis of Coherent Electron Diffuse Scattering for Diffractive Imaging: Jian Min Zuo1; Saran Pidaparthy1; Haoyang Ni1; Robert Busch1; hanyu Hou1; 1University of Illinois
Disorder in crystals produces diffuse scattering between Bragg reflection peaks. Traditionally, the study of crystal disorder has relied on the analysis of the volume integrated diffuse scattering with the help of modelling. Here we introduce a new diffractive imaging approach for the analysis of crystal disorder based on fluctuation analysis of the scattering of a coherent probe. We show that coherent diffraction of nm-sized electron probe produce the laser-speckles-like diffuse-scattering pattern, which records the interference of diffuse scattering in a disordered crystal. The fluctuations can be analyzed with the help of cepstral transformation and the Patterson function of the distortive part of the scattering potential can be obtained for diffractive imaging. We will demonstrated this principles using several examples, from dislocations in a semiconductor to battery materials.
4:10 PM Invited
Method Developments for High-efficient X-ray Coherent Diffraction Imaging: Yudong Yao1; Junjing Deng1; Henry Chan1; Jeffrey Klug1; Yi Jiang1; Barbara Frosik1; Zhonghou Cai1; Ross Harder1; Barry Lai1; Mathew Cherukara1; 1Argonne National Laboratory
X-ray coherent diffraction imaging (CDI) has gained tremendous success in providing nanoscale characterization in materials science, chemistry, solid-state physics, and biology communities. Combined with Bragg diffraction and/or scanning modalities (ptychography), one can achieve three-dimensional imaging of lattice strains and large field-of-view imaging of extended samples. As a scanning variant of CDI, ptychography imaging speed is currently limited by the available coherent flux and the scanning mechanism. Here we report on our recent developments in ptychography imaging technique and the improvement of reconstruction methods to increase the imaging throughput. In addition to the data acquisition speed, the data processing speed of CDI is determined by the phase retrieval algorithms, which are traditionally iterative and are therefore computationally expensive. Our recent development of an unsupervised physics-aware neural network (AutoPhaseNN) has shown great advantages in accelerating the data inversion in CDI, potentially enabling real-time imaging capabilities.
4:40 PM
"Similarity Mapping" Using Precession Electron Diffraction Data: Marcus Hansen1; Ainiu Wang1; Jiaqi Dong1; Kelvin Xie1; 1Texas A&M University
Grains in many material systems are not randomly oriented. Rather, they exhibit specific orientation relationships with the substrate or with each other. To efficiently map the same domains or variants is effort-demand, especially at the nano-scale. In this work, we report a method to map grains of similar orientations by computing the similarity between the reference pattern and the diffraction pattern of each pixel acquired using precession electron diffraction (PED). We first determine an optimal denoising algorithm. Next, "similarity maps" were generated to examine across the dataset to reveal the distribution of the same domain/variant of the system. Its application on epitaxially grown thin films and nanometer-size martensite will be discussed.
5:00 PM
Advances in Phase Retrieval for In Situ Observation of Dislocation Dynamics in Gold Microcrystals: Jason Nicholas Porter1; Ross Harder2; Wonsuk Cha2; Siddharth Maddali2; Yueheng Zhang3; Matthew Wilkin3; Anastasios Pateras4; Landon Schnebly1; Joshua Miller1; Robert Suter3; Anthony Rollett3; Richard Sandberg1; 1Brigham Young University; 2Argonne National Laboratory; 3Carnegie-Mellon University; 4Deutsches Elektronen-Synchrotron
The dynamic interplay between atomic dislocations and grain boundaries is poorly understood. This is partly because it occurs on the mesoscale---too large and slow for molecular dynamics modeling, but too small and fast for electron microscopy. We present recent advances in Bragg coherent diffraction imaging, specifically multipeak/multigrain coupled phase retrieval, which provide consistent reconstructions of the three-dimensional atomic structure of gold microcrystals on mesoscopic length scales. This allows a new type of experiment that allows nanometer-scale imaging of dislocation dynamics grain boundaries during in situ sample deformation. We present the results of these experiments, which are (at the time of abstract submission) planned for the fall and winter of 2022/23.
5:20 PM
Characterisation of Material Defects via Plasmon-enhanced Phase Imaging: Brian Abbey1; 1La Trobe University
We have recently demonstrated the feasibility of plasmon-enhanced colourimetric imaging of thin optically transparent films (Balaur et al., Nature, 2021) and of plasmon-enhanced quantitative phase imaging (Cadenazzi et al., Nature Photonics, 2021). We then extended these methods in order to examine the dielectric properties of ion-implanted thin films (Sadatnajafi, Advanced Functional Materials, 2022) and demonstrated that plasmon-enhanced colourimetric imaging and Monte-Carlo simulations could be used together for the quantitative determination of ion implantation dose with extreme sensitivity. Here, we demonstrate that the combination of phase contrast imaging and plasmon-enhancement enables a new approach to characterising material defects in thin films. The first experimental results using this novel technique will be presented.