In‐situ Bragg coherent X‐ray diffraction during tensile testing of an individual Au nanowire

Nanomechanical testing methods have drawn significant attention in both scientific and industrial research fields owing to unique deformation mechanisms in constrained volumes that underpin new property regimes. In-situ imaging equipment is now routinely employed to monitor the live evolution of material response during mechanical loading, with many of the testing developments tailored for electron microscopes (EMs). More recently, progress towards quantitative in-situ testing at synchrotron beamlines1–3 enabled by innovations in source brightness, focusing optics, and large size detectors has been made. Novel techniques such as Bragg coherent X-ray diffraction promise 3D information with phase information related to displacement fields (elastic strain, defects) within the material. However, despite the rich information that can be collected, many challenges arise in the realization of in-situ imaging of single nanostructures using such methods, including meticulous sample preparation and complex data analysis in retrieving phase information. In this work, we present the first successful systematic single nanowire tensile test while simultaneously recording 3D Bragg peaks using coherent X-rays. Defect free single crystalline \u3c110\u3e oriented Au nanowires were grown by physical vapor deposition4 and a 100 nm nanowire was harvested from the substrate and transferred to a nanotensile stage within a microelectromechanical system chip, which can be mounted to a coherent X-ray beamline. 3D Bragg peaks were recorded with nanofocused beam combined with 2D detector at each displacement step to discuss the evolution of strain and rotation of the nanowire during the tensile test. The movement of the peak sensitively depicted evolution of the deformation of the nanowire. In addition, the 3D Bragg coherent X-ray diffraction followed by phase retrieval has shown to reveal the internal strain state of nanostructure5 and this advanced technique is expected to reveal unique surface effects that mediate the overall mechanical performance of nano-scaled materials. 1. Cornelius, T. W. et al. In situ three-dimensional reciprocal-space mapping during mechanical deformation. J. Synchrotron Radiat. 19, 688–694 (2012). 2. Ren, Z. et al. Scanning force microscope for in situ nanofocused X-ray diffraction studies. J. Synchrotron Radiat. 21, 1128–1133 (2014). 3. Leclere, C. et al. In situ bending of an Au nanowire monitored by micro Laue diffraction. J. Appl. Crystallogr. 48, 291–296 (2015). 4. Richter, G. et al. Ultrahigh strength single crystalline nanowhiskers grown by physical vapor deposition. Nano Lett. 9, 3048–3052 (2009). 5. Haag, S. et al. Anomalous coherent diffraction of core-shell nano-objects: A methodology for determination of composition and strain fields. Phys. Rev. B 87, 35408 (2013)

Multi-wavelength Bragg coherent X-ray diffraction imaging of Au particles

International audienceMulti-wavelength (mw) Bragg coherent X-ray diffraction imaging (BCDI) is demonstrated on a single Au particle. The multi-wavelength Bragg diffraction patterns are inverted using conventional phase-retrieval algorithms where the dilation of the effective pixel size of a pixelated 2D detector caused by the variation of the X-ray beam energy is mitigated by interpolating the raw data. The reconstructed Bragg electron density and phase field are in excellent agreement with the results obtained from conventional rocking scans of the same particle. Voxel sizes of about 6 3 nm 3 are obtained for reconstructions from both approaches. Phase shifts as small as 0.41 rad, which correspond to displacements of 14 pm and translate into strain resolution better than 10 À4 in the Au particle, are resolved. The displacement field changes shape during the experiment, which is well reproduced by finite element method simulations considering an inhomogeneous strained carbon layer deposited on the Au particle over the course of the measurements. These experiments thus demonstrate the very high sensitivity of BCDI and mw-BCDI to strain induced by contaminations. Furthermore, mw-BCDI offers new opportunities for in situ and operando 3D strain imaging in complex sample environments

In situ tensile tests of single Au nanowires combined with coherent X-ray diffraction

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In situ Bragg coherent X-ray diffraction during tensile testing of an individual Au nanowire

International audienceWe report on systematic single defect free Au nanowires grown by physical vapor deposition in situ tensile tests while simultaneously recording 3D Bragg peaks using coherent X-rays. The trajectory of 3D Bragg peaks in reciprocal space during tensile testing allowed for measurements of the evolution of strains and rotations of the nanowire, thus sensitively uncovering the full deformation geometry of the nanowire. The transition from elastic to plastic deformation is accompanied by rotations of the nanowire as quantified by analysis of the motion of Bragg peaks, showing the importance of boundary conditions in interpreting nanoscale mechanical deformations

Study of the microstructure and stress induced during the crystallization of GeTe thin films

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Study of the microstructure and stress induced during the crystallization of GeTe thin films

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In-situ combined X-Ray diffraction and optical curvature measurements to study microstructure and stress induced during the crystallization of GeTe thin films

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In-situ combined X-Ray diffraction and optical curvature measurements to study microstructure and stress induced during the crystallization of GeTe thin films

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Study of Crystalline - Amorphous Phase Transition in Phase Change Materials

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Study of Crystalline - Amorphous Phase Transition in Phase Change Materials

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