Pair distribution function analysis applied to decahedral gold nanoparticles
Abstract not provided
Nakotte, H.↗
Engineering topics
Fohtung, E.
Publications and source records attributed to Fohtung, E..
Three-dimensional imaging of vortex structure in a ferroelectric nanoparticle driven by an electric field
Topological defects of spontaneous polarization are extensively studied as templates for unique physical phenomena and in the design of reconfigurable electronic devices. Experimental investigations of the complex topologies of polarization have been limited to surface phenomena, which has restricted the probing of the dynamic volumetric domain morphology in operando. Here, we utilize Bragg coherent diffractive imaging of a single BaTiO 3 nanoparticle in a composite polymer/ferroelectric capacitor to study the behavior of a three-dimensional vortex formed due to competing interactions involving ferroelectric domains. Our investigation of the structural phase transitions under the influence of an external electric field shows a mobile vortex core exhibiting a reversible hysteretic transformation path. We also study the toroidal moment of the vortex under the action of the field. Our results open avenues for the study of the structure and evolution of polar vortices and other topological structures in operando in functional materials under cross field configurations.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Observation of x-ray radiation pressure effects on nanocrystals
Bragg coherent diffractive imaging is a powerful technique that can be used to explore the internal structure and strain of nanoscale crystalline objects. During the data collection process, the Bragg peak typically stays within a small range of pixels on the x-ray sensitive area detector. Here, we report abrupt and irreversible Bragg peak movement during the coherent x-ray data collection process for both Pd nanocubes and a Ni nanowire. Here, we report that this phenomenon can be attributed to x-ray momentum transfer, also known as radiation pressure, to the nanocrystals. Understanding this effect is crucial given the anticipated coherent flux increases at next-generation synchrotron sources.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Nanoscale strain mapping in battery nanostructures
Coherent x-ray diffraction imaging is used to map the local three dimensional strain inhomogeneity and electron density distribution of two individual LiNi{sub 0.5}Mn{sub 1.5}O{sub 4−δ} cathode nanoparticles in both ex-situ and in-situ environments. Our reconstructed images revealed a maximum strain of 0.4%. We observed different variations in strain inhomogeneity due to multiple competing effects. The compressive/tensile component of the strain is connected to the local lithium content and, on the surface, interpreted in terms of a local Jahn-Teller distortion of Mn{sup 3+}. Finally, the measured strain distributions are discussed in terms of their impact on competing theoretical models of the lithiation process.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗