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Updated 10/04/2013
Functional Oxide Materials for Energy and Electronics Judith Driscoll
Oxides possess the whole range of materials functions, all the way from insulators to superconductors (with ferroelectrics, semiconductors, and magnetic materials, and a range of other functions in between). With this wide spread of functionalities as well as superior properties compared to conventional materials, they possess enormous potential to revolutionise the way we live. However, the complex compositions need to be precisely controlled in order to make the systems work in an optimal way. Materials science is therefore essential to provide the required performance enhancements for new applications. One first needs to know how best to make the materials, one also needs to understand and control surfaces and interfaces, and finally one needs to be able to design new materials and combinations thereof to achieve the better properties. |
Superconducting Spintronics Mark Blamire, Jason Robinson
Along with several other groups, we have shown how to create a new type of Cooper pair. These so-called triplet pairs consist of electrons with parallel spins and so are much more stable within a ferromagnet; this means that supercurrents can flow through ferromagnets for distances of tens or hundreds of nanometres. More importantly, because triplet pairs consist of electrons with parallel spins, these supercurrents can carry spin as well as charge. This discovery paves the way for an entirely new research field: that of superconducting spin electronics in which quantum coherent currents can transport spin and use it to perform information processing operations which are impossible in conventional spintronics. |
Oxide Interface Electronics Mark Blamire, Judith Driscoll
There are increasing numbers of examples of systems in which a property (e.g. conductivity or magnetism) appears at the interfaces between complex oxides which do not show the same property in the bulk. An example is the two-dimensional electron gas (2DEG) formed at the interface of SrTiO3/LaAlO3. We have shown that the carrier density and magnetism can be controlled by delta-doping the interface with transition metal ions. We have also shown that we can increase the carrier density by an order of magnitude by inserting a single unit cell of La-doped SrTiO3 at the interface and that the nature of the carriers is controlled by structural changes in the SrTiO3 surface. |
Thin Film development Zoe Barber
The Device Materials Group has a large thin film deposition facility based around magnetron sputter deposition and laser ablation. As well as providing a service to other members of the Department and the University as a whole there are a number of specific thin film research projects running:
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Electrocalorics Neil Mathur and Sohini Kar-Narayan
Heat and electricity may be interconverted using ferroelectric materials. Electrically driven temperature changes are rarely measured directly, but these electrocaloric effects may be mapped using scanning thermal microscopy (SThM). This technique involves rastering a tip with a resistive track (see image) that functions as a thermometer with resolution 0.1 K. Work on electrocalorics could ultimately lead to new methods of cooling.
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Magnetoelectrics Neil Mathur, Xavier Moya, Massimo Ghidini
Magnetic and electrical signals may be interconverted using ferroelectric and ferromagnetic materials that communicate via strain. Switching patterns may be observed, after different electrical and thermal histories, by collecting magnetic images obtained using in-house magnetic force microscopy (MFM), and photoemission electron microscopy (PEEM) with x-ray magnetic circular dichroism (XMCD) at Diamond Light Source (UK). Work on magnetoelectrics could ultimately be relevant to data storage and magnetic-field sensing. |
