Project overview
Multiferroic materials (or multiferroics) are single phase quantum materials that simultaneously exhibit more than one ferroic property including ferromagnetism, ferroelectricity, ferroelasticity or ferrotoroidicity. Multiferroics are of great interest because their different properties may work together in different ways and lead to exciting new potential applications, if we could understand this better. For example, a multiferroic material where an applied electric field can switch on (or off) magnetic properties of the material (and vice versa) can be utilised to develop (1) low power neuromorphic memory devices or (2) integrated circuits where the multiferroic functions as both interconnect and logic component. Electronic devices formed from such multiferroics can exceed 100 times the energy e?ciency of existing technologies and can therefore contribute significantly to reducing our dependence on fossil fuels. Multiferroics are generally found with varying regions of polarity, known as domains. The interfaces that separate these domains are known as domain walls. Domain walls in multiferroics are 2D systems that can host functional electronic and magnetic properties which could find utility in a new generation devices due to their agility and spatial mobility, if we could better understand them. Before multiferroics can find significant utility in a device setting, a clear understanding of the materials behaviour at the nanoscale is needed. To better understand multiferroic materials I will use a technique called Bragg coherent diffraction imaging (BCDI). This is a form of x-ray microscopy that doesn't requires focusing lenses and can permit high resolution three-dimensional imaging where the use of conventional optics is not feasible. BCDI of materials at the nanoscale provides information on atomic displacements from equilibrium with sub-angstrom sensitivity and nanometer resolution. The ability that BCDI has to directly image in three-dimensions structural properties of materials at the surface and in the bulk will greatly aid our understanding of the kinetics of dynamic phenomena that are central to the development of next generation materials and devices. Thus far and in the original proposal, e?orts have focussed on understanding quantum materials before they are employed in a device setting. It was shown in the programme of the original proposal that BCDI is able to reveal domain walls and domain types in three-dimensions in a single multiferroic hexagonal manganite nanocrystal. It was also shown that it is also possible to determine the spatial orientation of ferroelectric domains (relative to the lab frame of reference) in a single multiferroic nanocrystal using BCDI. In this fellowship renewal I will focus on in-operando Bragg coherent diffraction imaging of devices formed from a selection of multiferroic quantum materials. Emphasis will be placed on the study of devices where multiferroic materials form a functional component. Insight gained here will greatly aid our understanding of multiferroic materials in a device setting and will serve as a platform to develop next generation technologies based on such materials. The application of BCDI to the study of multiferroic materials and also devices can facilitate in enabling a wide range of next generation technologies that otherwise are inaccessible due to an incomplete understanding of their properties. This research proposal will be carried out in collaboration with Prof. J. Marty Gregg (Queens University Belfast), Prof. Dennis Meier (Norwegian University of Science and Technology), Dr. Daniel Porter (Diamond Light Source) and Prof. Paul Quinn (Ada Lovelace Centre).
