Measuring coefficient of thermal expansion of materials of micrometre size using SEM/FIB microscope with in situ MEMS heating stage.

A new method is proposed to measure the linear coefficient of thermal expansion (CTE) of solid metals and ceramics of micron-sized dimensions. This approach uses a focused ion beam (FIB) to extract and transfer a slab of the sample, typically (15-20) ×10 × (3-5) µm onto a Micro-Electro-Mechanical Systems (MEMS) in situ heating holder inside a scanning electron microscope (SEM). CTE is thereafter calculated by image correlating the change of length (ΔL) between the fiducial marks on the slab as a function of temperature, taking advantage of the temperature calibration of the MEMS heating holder and nanometre resolution of the scanning electron microscope. The CTE results are validated to be consistent with standard copper and silicon. We further demonstrate the method on a graphene platelet reinforced copper composite and a graphite filler phase isolated from a bulk sample, these represent materials that cannot be practically synthesised or isolated at the macro-scale. Errors associated with the measurement are discussed.

Dataset for stacking-mediated diffusion of ruthenium nanoclusters in bilayer graphene and graphite.

The data in this article are related to the research article "Stacking-Mediated Diffusion of Ruthenium Nanoclusters in Bilayer Graphene and Graphite" (J G McHugh, 2022). The data consists of Ru atom cluster intercalation calculations on graphene surfaces, within AA/AB bilayer graphene and graphite. We tabulate data for cluster sizes of 3, 4, 5 and 7 Ru atoms, which includes adsorption energies and diffusion energy barriers between all the highly symmetric sites in graphene/graphite. These data were obtained from density functional theory calculations. We provide tabulated data of relaxed structures that are useful for future classical interatomic potential fittings.

Data related to the mesoscopic structure of iso-graphite for nuclear applications.

The data in this article are related to the research article "Mesoscopic structure features in synthetic graphite" (März et al., 2018) [1]. Details of the manufacture of isostatically moulded graphite (iso-graphite), thin foil preparation by focused ion beams (FIB) for analysis, and characterisation methods are provided. The detailed structures of coke filler and binding carbon are presented through scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM) and Raman spectroscopy characterisation. Atomistic modelling results of mesoscopic structural features are included.

A fast algorithm for simulating flow-induced nucleation in polymers.

We present a fast computer simulation algorithm for high dimensional barrier crossing simulations. The algorithm is described with reference to the Graham and Olmsted (GO) model of flow-induced nucleation in polymers [R. S. Graham and P. D. Olmsted, Phys. Rev Lett. 103, 115702 (2009)]. Inspired by Chandler's barrier crossing algorithm [D. Chandler, J. Chem. Phys 68, 2959 (1978)], our algorithm simulates only the region around the top of the nucleation barrier, where the system deviates most strongly from equilibrium. When applied to the kinetic Monte Carlo (kMC) routine used in the GO model, our algorithm has two advantages: it requires very little additional coding; and it is simple enough to be applied to any barrier crossing problem that can be written in terms of a kMC simulation. Our fast nucleation algorithm is shown to vastly decrease the computer time required to perform the kMC simulations of high barrier crossing.