Imaging of Transient Structures Using Nanosecond in Situ TEM

Kim, Judy; LaGrange, Thomas; Reed, Bryan W.; Taheri, Mitra L.; Armstrong, Michael R.; King, Wayne E.; Browning, Nigel D.; Campbell, Geoffrey H.

doi:10.1126/science.1161517

Cited by 284 publications

(198 citation statements)

References 23 publications

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“…The time delay between the pump and probe laser pulses can be controlled from nanoseconds to hundreds of microseconds with a timing jitter of 1 ns. Further details on the configuration of the DTEM can be found in prior publications 21,22,27 were used for the nickel film and silicon nitride membrane, respectively. The thermophysical properties of nickel and silicon nitride are considered and a melting temperature suppression of ~1676 is assumed 33,34 .…”

Section: Methodsmentioning

confidence: 99%

Real-Time Observation of Nanosecond Liquid-Phase Assembly of Nickel Nanoparticles via Pulsed-Laser Heating

et al. 2012

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Using the dynamic transmission electron microscope (DTEM), the dewetting of thin nickel films was monitored at nanometer spatial and nanosecond timescales to provide insight into the liquidphase assembly dynamics. Correlated time and length scales indicate that a spinodal instability drives the assembly process. Measured lifetimes of the liquid metal agree with finite-element simulations of the laser-irradiated film. These results can be used to design improved synthesis and assembly routes toward achieving advanced functional nanomaterials and devices. Keywords assembly dynamics, dynamic transmission electron microscopy, pulsed-laser heating, thin-film dewetting LetterThe synthesis and organization of functional nanomaterials via bottom-up self-and directed assembly represents a critical challenge for the future of nanoscience. Generating arrays of nanoparticles with controlled size and spatial distributions is key to this challenge, and processes that exploit morphological instabilities offer the potential to attain these fine-scale spatially correlated structures. There has been long-standing interest in the capillarity and surface tension effects on morphological evolution in various materials systems, dating back to the work of Plateau 1 and Rayleigh 2 . Recently, pulsed-laser-induced dewetting of two-dimensional films 3-9 , one-dimensional lines and rings [10][11][12][13] , and lithographically patterned nanostructures 14,15 has demonstrated that understanding and controlling thin-film and Rayleigh-Plateau instabilities improves the ability to create organized metallic nanoparticle ensembles. Assembled particles have also been shown to "jump" or eject from one substrate and transfer to another depending on the energetics and dynamics of various laser-melted nanostructures [16][17][18] . Heretofore, the as described in the Methods section, the laser spot has a Gaussian profile and thus the radial profile of each image also contains thermal and temporal information. Figure 2d) shows an image taken long after a laser pulse to show the resultant nanoparticle structure in the same field of view. The images in Figure 2 were filtered to remove noise and irrelevant intensity variations using a 3x3 median filter followed by a local brightness and contrast equalization filter using a Gaussian kernel with an rms width of 33 pixels in the x-and y-directions. The raw images are provided in the Supporting Information.Dynamic selected-area diffraction (SAD) patterns were recorded as a function of time to complement the dynamic imaging and estimate the nickel liquid lifetime. Figure 3a) shows a series of SAD patterns taken at various times relative to the specimen pump laser's interaction with the specimen (including as-deposited and post-laser-pulse diffraction patterns using a long exposure time). The simulated diffraction pattern for polycrystalline nickel is included in the long-exposure as-deposited diffraction pattern. The conventional diffraction pattern from the asdeposited film shows broad diffraction ri...

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Section: Methodsmentioning

confidence: 99%

Real-Time Observation of Nanosecond Liquid-Phase Assembly of Nickel Nanoparticles via Pulsed-Laser Heating

et al. 2012

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“…An increase in temporal resolution brought on by faster than TV rate cameras would allow for improved imaging of domain propagation and help bridge the time resolution gap between standard in situ TEMs and other ultrafast techniques, such as the dynamic TEM (DTEM) technique, which is able to access nanosecond time scales with nanometer spatial resolution. 41,[43][44][45][46][47] …”

Section: Resultsmentioning

confidence: 99%

Accessing intermediate ferroelectric switching regimes with time-resolved transmission electron microscopy

Winkler¹,

Jablonski²,

Damodaran³

et al. 2012

Journal of Applied Physics

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Piezoresponse force microscopic study of ferroelectric (1−x)Pb(Sc1/2Nb1/2)O3−xPbTiO3 and Pb(Sc1/2Nb1/2)O3 single crystals J. Appl. Phys. 112, 052009 (2012) Piezoresponse force microscopy studies on the domain structures and local switching behavior of Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals J. Appl. Phys. 112, 052006 (2012) Antiferroelectric-like properties and enhanced polarization of Cu-doped K0.5Na0.5NbO3 piezoelectric ceramics Appl. Phys. Lett. 101, 082901 (2012) BiFeO 3 (BFO) is one of the most widely studied magneto-electric multiferroics. The magnetoelectric coupling in BiFeO 3 , which allows for the control of the ferroelectric and magnetic domain structures via applied electric fields, can be used to incorporate BiFeO 3 into novel spintronics devices and sensors. Before BiFeO 3 can be integrated into such devices, however, a better understanding of the dynamics of ferroelectric switching, particularly in the vicinity of extended defects, is needed. We use in situ transmission electron microscopy (TEM) to investigate the response of ferroelectric domains within BiFeO 3 thin films to applied electric fields at high temporal and spatial resolution. This technique is well suited to imaging the observed intermediate ferroelectric switching regimes, which occur on a time-and length-scale that are too fine to study via conventional scanning-probe techniques. Additionally, the spatial resolution of transmission electron microscopy allows for the direct study of the dynamics of domain nucleation and propagation in the presence of structural defects. In this article, we show how this high resolution technique captures transient ferroelectric structures forming during biasing, and how defects can both pin domains and act as a nucleation source. The observation of continuing domain coalescence over a range of times qualitatively agrees with the nucleation-limited-switching model proposed by Tagantsev et al. We demonstrate that our in situ transmission electron microscopy technique is well-suited to studying the dynamics of ferroelectric domains in BiFeO 3 and other ferroelectric materials. These biasing experiments provide a real-time view of the complex dynamics of domain switching and complement scanning-probe techniques. V C 2012 American Institute of Physics. [http://dx

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“…Previous publications [3][4][5][6][7][11][12][13] have described the basic principles and operation of the DTEM but have never fully documented the modifications to the electron optics and how these modifications have improved the imaging performance. In the present work, we report an upgrade to the LLNL DTEM that enables a factor-of-20 (or more) increase in the current that can be delivered to the sample, with optimized lens coupling that reduces the effect of condenser lens aberrations to levels small compared to thermal emittance.…”

Section: Introductionmentioning

confidence: 99%

“…It is now possible to drive material processes with various combinations of heat, gaseous and fluid environments, and focused lasers and to capture the evolution using either conventional video-rate acquisition or much faster acquisition ranging from nanosecond-scale real-space imaging of unique irreversible events [3][4][5][6][7] to femtosecond-scale diffraction, imaging, and spectroscopy of highly repeatable and/or reversible processes. [8][9][10] The associated instrument development is at present very rapid, frequently bringing to light new challenges and solutions appropriate to the new physical regimes in which these instruments operate.…”

Section: Introductionmentioning

confidence: 99%

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Solving the accelerator-condenser coupling problem in a nanosecond dynamic transmission electron microscope

Reed

LaGrange²,

Shuttlesworth³

et al. 2010

Review of Scientific Instruments

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We describe a modification to a transmission electron microscope (TEM) that allows it to briefly (using a pulsed-laser-driven photocathode) operate at currents in excess of 10 mA while keeping the effects of condenser lens aberrations to a minimum. This modification allows real-space imaging of material microstructure with a resolution of order 10 nm over regions several µm across with an exposure time of 15 ns. This is more than 6 orders of magnitude faster than typical video-rate TEM imaging. The key is the addition of a weak magnetic lens to couple the large-diameter high-current beam exiting the accelerator into the acceptance aperture of a conventional TEM condenser lens system. We show that the performance of the system is essentially consistent with models derived from ray tracing and finite element simulations. The instrument can also be operated as a conventional TEM by using the electron gun in a thermionic mode. The modification enables very high electron current densities in µm-sized areas and could also be used in a non-pulsed system for high-throughput imaging and analytical TEM.

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Imaging of Transient Structures Using Nanosecond in Situ TEM

Cited by 284 publications

References 23 publications

Real-Time Observation of Nanosecond Liquid-Phase Assembly of Nickel Nanoparticles via Pulsed-Laser Heating

Real-Time Observation of Nanosecond Liquid-Phase Assembly of Nickel Nanoparticles via Pulsed-Laser Heating

Accessing intermediate ferroelectric switching regimes with time-resolved transmission electron microscopy

Solving the accelerator-condenser coupling problem in a nanosecond dynamic transmission electron microscope

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