Webinar moderator, Professor Robert McGreevy, will open the webinar with a short overview of the LENS Initiative and the role of neutron scattering in working towards sustainable development goals.

The current climate change requires a global action, to which all sectors of society should contribute. Scientific progress provides us with powerful means to understand the physics behind the climate change, to predict the effects on our world and society, and to develop new technologies that would allow reducing the energetic footprint of humankind.

In this hunt for novel technologies, neutrons are used by scientists to characterise new materials from the Angstrom to the centimetre scale. In particular, the capability of highlighting light elements such as hydrogen and lithium, their magnetic properties, as well as the high penetration of neutrons, make them a crucial tool for the research and development addressed to fight climate change.

This talk will provide an overview on the use of neutron scattering applied to energy production trough organic photovoltaics, energy conversion in fuel cells, and energy consumption in an everyday household application. The reported examples will show the power of neutron reflectometry, neutron radiography, and small-angle neutron scattering to reveal the properties of the investigated materials.

The Earth’s climate is a highly complex, kinetically controlled balance of components and conditions within the atmosphere, that we know has been adversely affected by human activities. In order to monitor changes and predict future effects, intricate models are used, which rely on accurate parameters to describe these components and their lifetimes. One important component is aerosols. These affect our climate through both direct scattering and absorption of solar radiation, and indirectly through acting as cloud condensation nuclei, which in turn effect cloud formation and precipitation.

Much of this aerosol contains an insoluble mineral dust core and has an organic film coating, from either natural or anthropogenic sources. This organic film influences the climatic effect of the aerosol particle. However, the atmosphere is highly oxidising and these organic films will react and become unstable. By comparing the rate of this process to the lifetime of aerosols in the atmosphere their importance in climate modelling can be determined.

In this talk I will give a brief introduction to atmospheric aerosols and show how we are using neutron reflectometry to investigate oxidation of these organic films by key atmospheric species.

Design and implementation of advanced polymer membrane formulations for selective transport of ions and molecular species are critical for creating the next generations of batteries, fuel cells and separation devices. It is necessary to understand the detailed transport mechanisms over time- and length-scales relevant to the device operation, both in laboratory models and in working systems under realistic operational conditions. Neutron scattering techniques, including imaging, diffraction, quasi-elastic and small angle neutron scattering are unique tools for research to design, evaluate and implement advanced membrane technologies for renewable energies.

Domestic and industrial refrigeration applications contribute a substantial part to mankinds energy consumption. New technologies based on solid state caloric effects, such as magnetocaloric, barocaloric, elastocaloric and electrocaloric effect, promise considerable efficiency gains as compared to today’s vapor compression technology. Within our research we aim for a better understanding of the relation between the material structure and dynamics to guide a sustainable material design.

In caloric materials, applied fields (e.g. magnetic, electric, pressure, strain) lead to changes in entropy and in the adiabatic temperature. The observed caloric effects form the basis of the caloric refrigeration cycles. We are interested in the fundamental mechanisms of these caloric effects, which are not yet fully understood. In particular, we studied the magnetocaloric effect in the family of compounds Mn_5-xFe_xSi₃.

Neutron scattering experiments were crucial for the elucidation of the magnetic and crystalline structures and for the distinction of Mn and Fe [1]. In addition, inelastic neutron scattering investigations revealed that the application of a magnetic field induces (suppresses) fluctuations in the materials. These fluctuations are closely related to the inverse (direct) magnetocaloric effect observed in these compounds [2].

[1] N. Maraytta et al., J. Appl. Phys. 128, 103903, 2020 ; A. Eich et al., Mater. Res. Express 6, 096118, 2019; P. Hering, et al.,Chem. Mater. 27, 7128, 2015
[2] N. Biniskos, et al., Phys Rev B. 96, 104407, 2017; Biniskos et. al. Phys. Rev. Letters 120, 257205, 2018.

Webinar end 12:00