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Catalysis, Sensors and Data Storage
Nanoscale Magnetic Clusters
Magnetic nanostructures are interesting systems in which to study finite size
effects in magnetism. They are also important potential components in data
storage media and read/write heads, and are likely to be key to the technology
enabling the transition from the Gbits/in2 to Tbits/in2 regime. The design of
high magnetic moment and high anisotropy materials is vital to the achievement
of this goal. The programme at Reading covers the calculation and modelling of
moments and anisotropy in single element and binary clusters of sizes up to
about 1000 atoms. Reading is a partner in a collaborative programme to develop
advanced nanocluster materials for data storage applications.
Transition Metal Oxide Ultra-Thin Films
Transition metal oxides encompass a wide range of technologically important
materials ranging from gas sensors, catalytic supports and catalysts through to
gate dielectrics in the semiconductor industry. In all of these roles the
surface or interfaces of the oxide dominates the activity. The programme at
Reading aims to develop an understanding of the properties of the oxide surface,
the interface between oxides and metallic nanoparticles and the role of surface
defects and structures in growth mechanisms. A particular focus is the
determination of the mechanism by which the electronic and structural properties
of the reducible transition metal oxides can be tuned by variation of oxide
composition.
Modelling Island Nucleation and Growth
Atoms deposited on a surface diffuse and cluster together to form islands. These
islands are the building blocks of larger structures and so control of island
growth will yield control of crystalline nanostructures in general. Using
molecular dynamics and monte carlo simulations, we investigate the processes
(such as critical size for island stability, substrate pinning sites,
temperature, deposition rate) that control the size and spatial properties of
nucleated island arrays. To complement the experimental work on transition metal
oxide surfaces, we have initiated a modelling study of the surfaces and their
interface with metallic nanoparticles.
Encapsulated Nanomaterials
Reading has recently developed an important novel synthesis of a new form of
enclosed carbon stuffed with different materials, the stuffed carbon onions.
Such materials have widespread application and we highlight here a few of the
areas being pursued.
Magnetically separable carbon coated nano-sized catalysts
In applied heterogeneous catalysis the development of any novel catalysts or
processes are not only dependent upon the performance (activity & selectivity)
but also on the ease of catalyst separation from product. The main focus at
Reading has been on the appliance of new chemically-functionalized coatings
(fullerene carbon, silica & fluorinated compound coats) onto nano-catalysts,
rendering the nano-composite catalysts separable from a product mixture. The key
development was the thin but inert carbon coating to isolate the ferromagnetic
particles from the catalyst or reaction medium. This new class of catalysts hold
great promise for catalytic hydrogenation reactions in the liquid phase.
New Sensors
The synthesis, detailed testing and characterisation of such novel nano-sized
solid-state materials has revealed potentially important applications as new gas
and bio-sensors. Reading continues to receive support from EPSRC, Royal Society,
British Council, EU, industry, MOD/DERA, overseas funding bodies, etc in this
area. Close links have also been developed with sensor industries such as AH
Marks, Azur Environmental, Smith Detection, DERA.
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