Exploring Functional Materials by Understanding Beam‐Sample Interactions. (9th April 2022)

• Record Type: Journal Article
• Authors: Kisielowski, Christian; Specht, Petra; Rozeveld, Steve; Freitag, Bert; Kieft, Erik R.; Kang, Joo; Fielitz, Alyssa J.; Fielitz, Thomas R.; van Dyck, Dirk; Yancey, David F.
• Is Part Of: Advanced functional materials. Volume 32:Number 27(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-04-09
• Subjects: catalysis -- coherent inelastic electron scattering -- electron microscopy -- perturbations -- structure–function relationships -- temperature; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202201112
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Ultra‐low‐dose electron diffraction is performed with a double metal cyanide catalyst (DMC) to understand how electron irradiation stimulates structural alterations in functional materials. The commonly fading diffraction patterns with dose accumulation depend on the irradiated area and the beam current even when below 50 femto Amperes. Heat generation is observed and modeled by statistical, inelastic scattering events to describe how phonon excitations modulate radiation hardness. Specifically, the characteristic 1/e‐decay of Bragg intensities from DMC is delayed from 6 to 30 eÅ −2 at room temperature, which is comparable to the effect of embedding radiation soft matter in ice. DMC's radiation hardness is enhanced by a latency dose that forms during a phase transformation. This unifying model predicts that a critical dose rate exists for any material that varies between 0.1 and 10 4 eÅ −2 s −1 because of a material dependent competition of heat generation and spread. It shows that Brillouin scattering causes time dependent perturbations in electron irradiated solids that trigger time‐temperature‐transformations on a time scale of nanoseconds to microseconds at room temperature, which is not included in traditional models describing the decay of Bragg intensities by radiolysis. Abstract : Diffraction in the ultimate detection limit shows that electron scattering is coherent but inelastic including the low loss region where Brillouin scattering dominates. Among other aspects, it imprints a time dependence on the radiation hardness of any materials and offers new ways to investigate functional behavior at high spatiotemporal resolution (1 Å, 1 ps) by electron microscopy.