New insights into the glass transition

What happens to a liquid when you cool it to obtain a glass? Despite the apparent simplicity of this question, understanding glass transition has defied the previous efforts of many theorists, and has become has become one of the "most interesting unsolved problem in solid state theory", according to eminent scientists. This is particularly exciting because we now claim to understand such exotic states of matter such as superfluidity and superconductivity, yet cooling a liquid to obtain glass comes across as conceptually simple.

Structure of an amorphous metal-organic framework structure

Metal organic framework materials form as three-dimensional network structures with metal cations linked via organic ligands. One example is zinc imadazolate, in which the zinc cations are tetrahedrally coordinated to the imadazolate ligands to form structures that are analogous to phases of silicates, including zeolite structures. The elusive structure is the amorphous analogue of silica, which cannot be formed by freezing from the melt. We recently found that an amorphous phase can be formed by heating the structure of one crystalline phase, ZIF-4, prior to its transformation to a higher-density phase.

Spin-loss mechanisms in organic spin valves - separating interfacial and bulk contributions

Electronic devices that utilise the spin degree of freedom hold unique prospects for future technology. They promise low-power logic, possibly at the quantum level, and the combination on the same chip of communication, logic and memory elements. When combined with the properties of organic materials, which have low manufacturing costs, are mechanically flexible and are energy efficient, there is considerable potential for extending the already great scope that spintronic devices have. Furthermore, it has recently been shown that organic materials can preserve the spin information for extremely long times – in some cases over a million times longer than their conventional counterparts. This opens up new horizons in the field of spintronics and may lead to an entirely new generation of spin-enabled devices.

Local insight into electric ordering

Hybrid perovskite analogues – materials that combine small organic ions with metals to create a framework structure – have important applications in fields ranging from solar power generation to computing and data storage. In a recent experiment, CCMMP PhD student Helen Duncan, together with her supervisors Dr Anthony Phillips and Prof. Martin Dove, used neutron scattering data from the GEM instrument at ISIS Neutron and Muon Source to investigate one such material, dimethylammonium manganese(II) formate. Analysing the data using the reverse Monte Carlo method revealed the local structure of the material: exactly the detail that is missed by conventional crystallographic techniques that yield the spatial average structure.

Liquid-like metals under pressure

There is currently a surge of interest in mechanical behaviour of nanoscale systems with the aim to understand if metastability in a variety of materials can be achieved, explained and indeed exploited. Since the dawn of nanotechnology it has been known that size effects have significant consequences for the atomic arrangements, electronic properties and behavior of matter under extreme pressure. It has been shown that exploring size effect is crucial for understanding mechanical properties of materials.  Furthermore, behavior of matter under critical pressure–temperature conditions provides vital guidance in the search for materials with novel properties.