Spectroscopic Detection of Magnetic Scattering and Quasiparticles at Atomic Resolution in the Electron Microscope

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Semiconductor devices that have revolutionised science and technology are based on the ability to control the transport of electron charges in nanoscale-sized materials. However, the miniaturisation of transistors, the building blocks of logic devices, is reaching a bottleneck and the speed of charge transport is reaching its physical limits, highlighting the need for new device designs. Electrons being used in electronic devices carry an additional piece of information called spin. So-called spintronic devices exploit this electron spin, in addition to its charge, to transport information more quickly and effectively. As a result, they have the potential to overcome the limitations of conventional electronics. A way to implement this concept is through the creation in spintronic materials of 'information waves', periodic oscillations of the spin of charge carriers, which propagate within the devices. These spin waves are also called 'magnons'. In order to effectively use these magnons in new electronics, it is essential to visualise and understand how they are generated and transferred within spintronic devices across interfaces or contacts and thus shed light on how effectively information can be carried. Up to now, no experimental tool or method has been available to provide this information at the relevant nano- or even atomic scale.Era-defining technological and methodological developments in the last decade in the field of electron microscopy have seen the energy resolution of current-generation instruments reach the sub-5meV level while retaining atomic-scale spatial resolution. Such ground-breaking capabilities should enable the detection of energy losses incurred by electron probes scattered within samples being observed when exciting magnons, which lie in this meV energy range. This International Centre-to-Centre Collaborative project thus assembles a team whose research and expertise are at the forefront of scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS), with extensive experience in generating knowledge, tools, and methodologies in the fields of advanced electron microscopy and modelling of electron scattering, with a view to demonstrate magnon EEL spectroscopy in the electron microscope.The project aims to develop the experimental and theoretical tools that will allow us to detect and visualise magnons at the nano and atomic scale with electron-based spectroscopy. A main goal is to fingerprint unambiguously the spectroscopic signature of magnons in materials for spintronic applications and to correlate this observation with the wealth of structural and chemical information that analytical electron microscopy can provide. State-of-the-art computational tools will allow us to guide and design experimental parameters and to rationalised experimental results. This project will provide a new way of studying the fundamentals of magnetic ordering and spin wave excitations in the solid state and it will provide a complete picture of magnetic and electronic properties of materials and devices.