Editorial: Tipping points in societies

Thermo-Magnetostrictive Effect for Driving Antiferromagnetic Two-Dimensional Material Resonators

Magnetostrictive coupling has recently attracted interest as a sensitive method for studying magnetism in two-dimensional (2D) materials by mechanical means. However, its application in high-frequency magnetic actuators and transducers requires rapid modulation of the magnetic order, which is difficult to achieve with external magnets,...

Jamming in soft disk packings

This thesis considers the mechanical properties of amorphous solids such as foams, emulsions, and granular media. Each of these systems consists of “particles” (bubbles, droplets, grains) in a dense, disordered structure. As a system is compressed, it eventually forms enough contacts between particles that it can support a load, including...

Higher-order phenomena in nanomechanics of two-dimensional material membranes

This thesis studies higher-order material properties* and effects in van der Waals crystals, such as anisotropic Young’s modulus, magnetostriction, and non-trivial thermal expansion effects near magnetic and electronic phase transitions, that can affect the nanomechanical motion ofmultilayer two-dimensional (2D) material membranes. These...

Applied and fundamental studies of vibrating 2D membranes

This thesis encompasses both applied and fundamental studies of suspended van der Waals materials. Chapters 1 and 2 give an introduction to the field of 2D materials and some of the critical methods which facilitate the study of the suspended structures. In Chapters 3 and 4 we focus on the applications of graphene in barometric pressure sensors...

Effect of Structural Defects and Impurities on the Excited State Dynamics of 2D BA₂PbI₄ Perovskite

In this work, we show that the quality of the precursor and the thin film preparation strongly affect the optoelectronic properties of the 2D perovskite BA₂PbI₄. 2D perovskites with alkylammonium organic cations such as butylammonium (BA) are relatively soft structures that exhibit large dynamic disorder and phase...

Revealing operando transformation dynamics in individual Li-ion electrode crystallites using X-Ray Microbeam Diffraction

For the development of next-generation batteries it is important to understand the structural changes in electrodes under realistic non-equilibrium conditions. With microbeam X-ray diffraction it is possible to probe many individual electrode grains concurrently under non-equilibrium conditions in realistic battery systems. This makes it...

High temperature phase transition of mixed (PuO2 + ThO2) investigated by laser melting

A laser heating approach combined with fast pyrometry in a thermal arrest method was used to provide new data for the melting/solidification phase transition in mixed (PuO2 + ThO2) at high temperature. At low concentration of ThO2 in PuO2 a minimum in the solidification temperature in the pseudo binary (PuO2 + ThO2) was observed. The minimum was...

The solidification behaviour of the UO2–ThO2 system in a laser heating study

The high-temperature phase diagram of the UO2–ThO2 system has been experimentally revisited in the present study for the first time since 1970, using a laser heating approach combined with fast pyrometry in a thermal arrest method. The melting/solidification temperature, which is of fundamental information for a reactor design was studied here....

Taming the first-order transition in giant magnetocaloric materials

Large magnetically driven temperature changes are observed in MnFe(P,Si,B) materials simultaneously with large entropy changes, limited (thermal or magnetic) hysteresis, and good mechanical stability. The partial substitution of B for P in MnFe(P,Si) compounds is found to be an ideal parameter to control the latent heat observed at the Curie...

Improved atomic-scale simulations of silicon

Although over the past years huge progress has been made in silicon research and silicon can be regarded as one of the best studied chemical elements, even more precise control and understanding of the material is needed as dimensions of electronic elements shrink towards the deep nanolevel. At this scale, experiments are not always sufficient...

Influence of additives on structure and thermal stability of ammonium nitrate