TY - JOUR A1 - Feng, W. A1 - Gemming, T. A1 - Giebeler, L. A1 - Qu, J. A1 - Weinel, Kristina A1 - Agudo Jácome, Leonardo A1 - Büchner, B. A1 - Gonzalez-Martinez, I. T1 - Influence of magnetic field on electron beam-induced Coulomb explosion of gold microparticles in transmission electron microscopy N2 - In this work we instigated the fragmentation of Au microparticles supported on a thin amorphous carbon film by irradiating them with a gradually convergent electron beam inside the Transmission Electron Microscope. This phenomenon has been generically labeled as ‘‘electron beam-induced fragmentation’’ or EBIF and its physical origin remains contested. On the one hand, EBIF has been primarily characterized as a consequence of beam-induced heating. On the other, EBIF has been attributed to beam-induced charging eventually leading to Coulomb explosion. To test the feasibility of the charging framework for EBIF, we instigated the fragmentation of Au particles under two different experimental conditions. First, with the magnetic objective lens of the microscope operating at full capacity, i.e. background magnetic field 𝐵 = 2 T, and with the magnetic objective lens switched off (Lorenz mode), i.e. 𝐵 = 0 T. We observe that the presence or absence of the magnetic field noticeably affects the critical current density at which EBIF occurs. This strongly suggests that magnetic field effects play a crucial role in instigating EBIF on the microparticles. The dependence of the value of the critical current density on the absence or presence of an ambient magnetic field cannot be accounted for by the beam-induced heating model. Consequently, this work presents robust experimental evidence suggesting that Coulomb explosion driven by electrostatic charging is the root cause of EBIF. KW - Electron beam-induced fragmentation KW - Coulomb explosion KW - X-ray diffraction KW - Lorenz transmission electron microscopy KW - Electron beam-induced charging PY - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-600170 VL - 262 SP - 1 EP - 8 PB - Elsevier B.V. AN - OPUS4-60017 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gonzalez-Martinez, I. A1 - Weinel, Kristina A1 - Feng, W. A1 - Agudo Jacome, Leonardo A1 - Gemming, T. A1 - Büchner, B. T1 - Hybrid tungsten-carbon 2D nanostructures via in-situ gasification of carbon substrates driven by ebeam irradiation of WO2.9 microparticles N2 - Since the TEM has the capacity to observe the atomic structure of materials, in-situ TEM synthesis methods are uniquely suited to advance our fundamental understanding of the bottom-up dynamics that drive the formation of nanostructures. E-beam induced fragmentation (potentially identified as a manifestation of Coulomb explosion) and electron stimulated desorption (ESD) are phenomena that have received attention because they trigger chemical and physical reactions that can lead to the production of various nanostructures. Here we report a simple TEM protocol implemented on WO2.9 microparticles supported on thin amorphous carbon substrates. The method produces various nanostructures such as WC nanoparticles, WC supported films and others. Nevertheless, we focus on the gradual graphitization and gasification of the C substrate as it interacts with the material expelled from the WO2.9 microparticles. The progressive gasification transforms the substrate from amorphous C down to hybrid graphitic nanoribbons incorporating W nanoparticles. We think these observations open interesting possibilities for the synthesis of 2D nanomaterials in the TEM. KW - Transmission electron microscope (TEM) KW - in-situ synthesis KW - Tungsten carbide KW - Nanoribbons KW - Coulomb explosion PY - 2023 U6 - https://doi.org/10.1088/1361-6528/acf584 SN - 0957-4484 VL - 34 IS - 49 SP - 1 EP - 15 PB - IOP Publishing AN - OPUS4-58279 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -