Caractérisation 4D-STEM de matériaux sensibles : Etude de l’astéroide Ryugu et des météorites carbonées - Université de Lille Accéder directement au contenu
Communication Dans Un Congrès Année : 2023

Caractérisation 4D-STEM de matériaux sensibles : Etude de l’astéroide Ryugu et des météorites carbonées

Résumé

Four-dimensional scanning transmission electron microscopy (4D-STEM) has emerged as a powerful tool for the characterization of beam-sensitive materials, enabling structural analysis at the nanometer scale with minimal radiation damage. In a 4D-STEM experiment, a onverging electron probe is scanned across a thin area of a sample and a 2D diffraction pattern is recorded at each scan position, yielding a four-dimensional dataset (Fig 1). 4D-STEM coupled with the new direct electron detection technology allows for the acquisition of diffraction information with unprecedented sensitivity and speed. The unique advantages of 4D-STEM make it an attractive option for studying a wide range of materials, including those that have previously been challenging for structural characterization using conventional transmission electron microscopy (TEM) techniques. Among these materials, carbonaceous meteorite and asteroid samples represent some of the most primitive specimens in our solar system, containing a wealth of information about its formation and evolution. The study of such samples is rendered particularly difficult due to the very fine scale mixing of beam sensitive phases composing their phyllosilicate matrix. In this work, we report an application of the 4D-STEM technique to investigate the mineralogy of Ryugu asteroid samples from the Japanese mission Hayabusa2 [1] and the composition-close Orgueil carbonaceous meteorite. Experiments have been carried out on a probe corrected 60-300 kV Thermo Fisher Titan Themis (S)TEM coupled with a Medipix 3 direct electron detector (Quantum Detectors) installed behind a post-column high-resolution energy filter (Gatan Quantum ERS/966), enabling energy-filtered 4D-STEM. Data have been analyzed using the open-source Python packages py4DSTEM and HyperSpy software. We introduce an analysis protocol for mapping the different mineralogical phases in the phyllosilicate matrix of the samples (Fig 2). We find that the serpentine in Ryugu is, with a good level of confidence, present in the form of Lizardite. We also map the interplanar spacing in the smectite phase (Fig 2). We will discuss the implications of such findings.
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Dates et versions

hal-04266395 , version 1 (31-10-2023)

Identifiants

  • HAL Id : hal-04266395 , version 1

Citer

Bahae-Eddine Mouloud, Damien Jacob, Maya Marinova, Corentin Le Guillou, Hugues Leroux, et al.. Caractérisation 4D-STEM de matériaux sensibles : Etude de l’astéroide Ryugu et des météorites carbonées. Colloque de la Société Francaise des Microscopies (Sfmu), Jul 2023, ROUEN, France. ⟨hal-04266395⟩
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