20th May 2013
The formation and evolution of oxide particles in oxide-dispersion-strengthened ferritic steels during processing
The effects of individual stages of oxide dispersion strengthened alloy processing has been investigated by systematic characterization of the material by atom probe tomography and transmission electron microscopy. The effect of mechanical alloying with Fe2Y compared with Y2O3 to incorporate Y into the system during mechanical alloying has also been investigated. This has provided some key insights into the formation of nanoparticles and larger oxides in ODS steels. It can be concluded that the size and compositionof the nanoparticles cannot be controlled by thermal treatments before or after consolidation at industrially applicable conditions
20th May 2013
Effect of grain boundary orientation on radiation-induced segregation in a Fe–15.2 at.% Cr alloy
In an effort to develop a full mechanistic understanding of radiation induced segregation and radiation induced depletion, a systematic approach combining orientation imaging, site-specific specimen preparation and three-dimensional atomic-scale analysis has been developed to characterize the behaviour of Cr and C at grain boundaries during irradiation. This methodology has been applied to a Fe–15.2 at.% Cr alloy to investigate the effects of grain boundary misorientation, irradiation depth and impurities. Systematic differences in Cr segregation are reported as a function of grain boundary character and irradiation conditions.
24th April 2013
Recent graphene publications
A team led by Dr Jamie Warner and his DPhil student Alex Robertson, from the fullerenes, nanotubes and graphene (FNG) group in the Department of Materials at Oxford, have published three papers in high impact journals (Nano Letters, ACS Nano and Nanoscale) on the atomic structure of graphene.
In the Nano Letters paper, the team demonstrate the ability to dope graphene with single metal atoms at sub-10nm spatial accuracy. This approach is at least two orders of magnitude better than other reports. The dynamics of the Fe atom within the vacancies was studied and switching between predicted magnetic and non-magnetic states was captured in real time.
In the ACS Nano paper, monovacancies in graphene were studied with unpreceedented spatial resolution. Two distinct configurations of the monovacancy in graphene were observed for the first time. This work provides the most detailed characterization to date of the exact structural form of monovacancies in graphene. Dynamics of monovacancy movement were also captured in real time and help understand the pathways of vacancy migration.
An invited feature article in the journal Nanoscale summarizes several publications from the FNG group over the past couple of years on the atomic resolution imaging of graphene using Oxford's state-of-the-art aberration corrected high resolution transmission electron microscope located at Begbroke Science Park.
15th April 2013
How safe is that Nuclear Reactor?
Professor George Smith FRS have been awarded the IoM3 Materials World Publication Award 2013, for his article entitled "How safe is that Nuclear Reactor?", which was published 7 May 2012 edition of Materials World.
4th March 2013
Catching Quantum Mechanics in the act
Researchers from Oxford, Delft and London have demonstrated a form of quantum superposition first predicted twenty years ago by the Israeli physicists Yakir Aharonov and Lev Vaidman.
The work is published in Proceedings of the National Academy of Sciences doi:10.1073/pnas.1208374110
Dr Richard George commented, "Our confirmation of these subtle quantum predictions is an important step on the road to transplanting quantum mechanics from a theoretical and laboratory curiosity and into the devices which we use in commerce and everyday life. Our vision is to scale up and build computers in which every ‘bit’ is replaced with a ‘quantum bit’ that uses superposition as an integral part of their operation."
1st February 2013
Controlling the Orientation, Edge Geometry and Thickness of Chemical Vapor Depostion Graphene
A new way of growing graphene without the defects that weaken it and prevent electrons from flowing freely within it could open the way to large-scale manufacturing of graphene-based devices, with applications in fields such as electronics, energy, and healthcare.
A team led by Nicole Grobert has overcome a key problem that occurs when growing graphene through chemical vapour deposition, by using the copper substrate to control the orientation of growing graphene flakes. The team demonstrates on Cu(111) and Cu(101) that these graphene flakes, called ‘domains’, are well-aligned, which will create a neater, stronger, and more ‘electron-friendly’ material.
The Oxford-led team, which includes researchers from Forschungszentrum Juelich Germany, the University of Ioannina Greece, and Renishaw plc, has also shown that it is possible using the new technique to selectively grow bilayer domains of graphene – a double layer of closely packed carbon atoms – which are of particular interest for their unusual electrical properties.
Full paper: ACS Nano 24 Jan 2013
Oxford University News article: Routes towards defect-free graphene
Interviews: AtoZ interview
Other websites publishing this news: Graphene Info; Pan European Networks; The Engineer; Materials Knowledge Transfer Network; Science Business; Graphene Times; Science News Line; My Science; E&T Engineering & Technology Magazine; Hilgertmnetta9 blog; Radio Electronics; Microscopy Analysis; Today Topics; AzoNano; Press Trust; Materialsgate; NanoVIP nanotechnology news; Nanotechnology Today; Science World Report; World Industrial Reporter; Compute Scotland; New Electronics; Electronics Weekly; Tech Tech Boom; Radio Electronics; Global Update News; DPA; Scott’s Blog; Punchline Gloucester;
14th December 2012
How the crystallography and nanoscale chemistry of the metal/oxide interface develops during the aqueous oxidation of zirconium cladding alloys
Aqueous corrosion and hydrogenation have become major limiting factors to the use of zirconium alloys as fuel cladding and assembly components in water-cooled nuclear reactors. The metal–oxide interface has been a particular focus of previous research, but there is still no clear understanding of what is present at the interface at different stages of the complex oxidation process.
A collaboration between Oxford Materials and Manchester University has used the latest generation of high resolution analysis techniques to correlate the microstructure of Zr alloys with the key mechanisms of oxidation. Acta Materialia 60 (2012) 7132–7149
12th December 2012
Ideal Energy-Level Alignment at the ZnO/P3HT Photovoltaic Interface
Hybrid organic-inorganic solar cells based on ZnO and P3HT have been the subject of significant interest over the past few years owing to their potential for low-cost and scalable solar energy technology. Despite the tremendous progress that has been made in this area, device efficiencies are still below 2%, in part due to low open-circuit voltages.
Keian Noori and Feliciano Giustino have performed the largest first-principles calculation on the ZnO/P3HT interface to date in order to shed light on the mechanisms determining the photovoltage in these systems.
According to the calculations the ideal open-circuit voltage of this interface, i.e., the maximum voltage that can be achieved in the absence of defects, is significantly higher than previous estimates. This finding makes ZnO/P3HT blends attractive for nanostructured photovoltaics.
This study, currently featured as the Front Cover of Advanced Functional Materials and tagged as one of the "Hottest Articles" of the journal, suggests that there is substantial room for improvement in ZnO/P3HT-based solar cells and calls for a renewed effort to tailor this interface at the nanoscale. The article is available for free download from the Advanced Functional Materials website.
11th November 2012
Spatial Control of Defect Formation in Graphene at the Nanoscale
A team led by Oxford University scientists report in Nature Communications a new approach to engineering graphene's atomic structure with unprecedented precision. For further reading see: http://www.ox.ac.uk/media/science_blog/121024.html.
7th November 2012
Solid Immersion Facilitates Fluorescence Microscopy with Nanometer Resolution and Sub-Ångström Emitter Localization
A collaboration between Oxford Materials, Bristol University and the University of Goettingen has achieved a record spatial resolution of 2.4 nm in the optical microscopy of NV centres in diamond.
Wildanger, D., Patton, B. R., Schill, H., Marseglia, L., Hadden, J. P., Knauer, S., Schönle, A., Rarity, J. G., O'Brien, J. L., Hell, S. W. and Smith, J. M. (2012), Solid Immersion Facilitates Fluorescence Microscopy with Nanometer Resolution and Sub-Ångström Emitter Localization. Adv. Mater.. doi: 10.1002/adma.201203033