Nanomaterials derive their electronic, magnetic, and optical properties from their specific nanostructure. In most cases, nanostructured materials and their properties are defined during the materials growth, and nanofabrication techniques, such as lithography, are employed subsequently for device fabrication. Herein, a perspective is presented on a different approach for creating nanomaterials and devices where, after growth, advanced nanofabrication techniques are used to directly nanostructure condensed matter systems, by inducing highly controlled, localized, and stable changes in the electronic, magnetic, or optical properties. Then, advantages, limitations, applications in materials science and technology are highlighted, and future perspectives are discussed.
Spin waves represent the collective excitations of the
magnetization
field within a magnetic material, providing dispersion curves that
can be manipulated by material design and external stimuli. Bulk and
surface spin waves can be excited in a thin film with positive or
negative group velocities and, by incorporating a symmetry-breaking
mechanism, magnetochiral features arise. Here we study the band diagram
of a chiral magnonic crystal consisting of a ferromagnetic film incorporating
a periodic Dzyaloshinskii–Moriya coupling via interfacial contact
with an array of heavy-metal nanowires. We provide experimental evidence
for a strong asymmetry of the spin wave amplitude induced by the modulated
interfacial Dzyaloshinskii–Moriya interaction, which generates
a nonreciprocal propagation. Moreover, we observe the formation of
flat spin-wave bands at low frequencies in the band diagram. Calculations
reveal that depending on the perpendicular anisotropy, the spin-wave
localization associated with the flat modes occurs in the zones with
or without Dzyaloshinskii–Moriya interaction.
The application of numerical simulation to wearable airbags for motorcyclists is relatively recent and only few works about this topic can be found in the literature. This research uses multi-physics simulation to analyse a new wearable airbag geometry, primarily designed to protect the shoulders of motorcycle riders, with the aim of assessing the effect of inflation pressure on the protection performance. The finite element model of the airbag employs a simple linear-isotropic material model, calibrated though the comparison between experimental and numerical outcomes of a drop test, together with the analysis of the airbag inflated geometry. The finite element model of the wearable device is then fitted to a dummy model and a human body model, in order to be used in a parametric analysis. Two set-ups are considered. The first is a thorax impact test, used to assess the effect of inflation pressure on chest protection. A modification to the bag geometry is also proposed and tested on this configuration. The second set-up is a shoulder impact test, used to assess the effect of inflation pressure on shoulder protection. In both tests an optimal inflation pressure can be found, but the maximization of shoulder protection proved more critical and should therefore drive the choice of this parameter.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.