Microscopy Group
News: Archive for 2002


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December 2002

CONGRATULATIONS to Professor Colin Humphreys on being awarded a CBE in the New Year Honours, for "services to science as a researcher and communicator".



December 2002

Charge-ordered ferromagnetic phase in La0.5Ca0.5MnO3

J C Loudon, N D Mathur and P A Midgley
Nature 420 (2002), 797.

The above paper shows that charge order exists both in ferromagnetic regions and in regions that have no net magnetization in the mixed-valent manganite La0.5Ca0.5MnO3.

The figure on the right shows a colour image of the magnetic microstructure in this material, derived from electron holographic data overlaid onto a Fresnel defocus image. Different colours correspond to different directions of magnetic induction in the sample.

Click here to download the paper in pdf format [225 kB ].



December 2002

Direct imaging of nanoscale magnetic interactions in minerals

R J Harrison, R E Dunin-Borkowski and A Putnis
Proc. Nat. Acad. Sci.99 (2002), 16556.

The above paper describes the characterisation of the magnetic microstructure in a natural, finely exsolved intergrowth of magnetite blocks in an ulvospinel matrix at a spatial resolution of better than 10 nm.

The figure on the right shows the magnetic microstructure in this sample, which is influenced both by the shapes of the individual magnetite blocks and by magnetostatic interactions between them. Different colours correspond to different directions of magnetic induction in the sample.

Click here to download the paper in pdf format [650 kB ].



December 2002

Click here to see some photos from this year's EM group Christmas party, which was held in Peterhouse. Thanks to Dave Cooper and Matthew Weyland for the photos.



December 2002

CONGRATULATIONS to Alison Twitchett and Duncan Alexander on passing their Ph.D. vivas.



Alison's thesis title was 'Electron holography of semiconductor devices'. Her examiners were Colin Humphreys and Hannes Lichte from Dresden.



Duncan's thesis title was 'Intermetallic phase transformations in 3XXX aluminium alloys'. His examiners were Paul Midgley and Yves Brechet from Grenoble.



December 2002

CONGRATULATIONS to Ton van Helvoort on passing his Ph.D. viva. His thesis title was 'Microstructural characterisation of electrostatic bonding'.



November 2002

CONGRATULATIONS to Chris Boothroyd and to Yeng-Ming Lam on the occasion of their wedding, which took place in Singapore on 30 November, 2002.

Click here to see some more photos.



November 2002

CONGRATULATIONS to Rudi Meyer on passing his Ph.D. viva. His thesis title was 'Quantitative automated object wave restoration in high-resolution electron microscopy'.



November 2002

WELCOME to Dr Diana Zhi.



Diana, who joins us from Imperial College, will be working on electron holography of semiconductor devices.





October 2002

WELCOME to Dr Lydia Laffont.

Lydia joins us from Toulouse to work on electron tomography. She has just completed her Ph.D. on electron energy loss spectroscopy of carbon-based materials.



October 2002

WELCOME to our new Ph.D. students Ryan Chong, Dave Cooper, Susan Cox, Philippa Somodi and Tim Yates.



Ryan Chong will be working on electron holography of nanostructured magnetic materials.



Dave Cooper will be working on electron holography of semiconductor devices.



Susan Cox will be working on colossal magneto-resistive materials.



Philippa Somodi will be working on the theory behind electron holography of semiconductor devices.



Tim Yates will be working on the automation of electron tomography.



October 2002

FAREWELL to Dr Connie Schonjahn, Dr Steffi Friedrichs and Katherine Langley.



Connie Schonjahn is moving to a PostDoctoral position in Sheffield.



Steffi Friedrichs is taking up a research fellowship in Oxford.



Katherine Langley will be completing her Ph.D. in Oxford, where her supervisor Angus Kirkland has been appointed to a staff position.



September 2002

Visions of Science competition 2002

CONGRATULATIONS to Rafal Dunin-Borkowski on receiving an award in the 'Science close-up' category of the Daily Telegraph/ Novartis Visions of Science competition for the second year running.

Click here to access the Visions of Science website.

The story was featured in CAM magazine, in the Cambridge Evening News and in the Cambridge Town Crier.



Rafal's winning entry shows the magnetic microstructure of a naturally occurring rock sample. Rocks such as these record the direction of the earth's magnetic field with great stability over geological times. Small regions of magnetite, which are each about 100 nm in size, are outlined in white in the figure. In between these magnetite 'blocks' are regions of non-magnetic titanomagnetite. The black lines show the magnetic field lines in the sample, measured using electron holography. The colours show the direction of the local magnetic field in each magnetite block. In this sample, the stabilty of the magnetic microstructure arises from strong interactions between adjacent magnetite blocks, as well as from their shape anisotropy.

This work was carried out with Richard Harrison from the Department of Earth Sciences in Cambridge and Andrew Putnis from the University of Munster in Germany.



September 2002

CONGRATULATIONS to Stephen Lloyd on being awarded second prize in the Microscopy Society of America micrograph competition in Quebec City.

Congratulations also to Stephen for winning first prize in the books competition in the June 2002 issue of Materials World.



Stephen's winning micrograph 'It went that-a-way' shows a bright field TEM image of a single crystal InGaAs superlattice, period 125 nm, grown on InP.

The structure is coherently strained with alternating compressive and tensile stress by varying the In content of the layers. Here the thinner layers are tensile strained. The sample has been bent in 3-point loading at 500 C to cause compressive yielding in the multilayer. An electron transparent section through the superlattice was made using a focused ion beam microscope. The structure has deformed by shearing along {111} planes, creating surface steps. Around 100 dislocations would be required to create the step shown. The ruck in the structure could either have been created by a dislocation source operating in the third compressive layer from the surface, or from dislocations moving from the substrate on slip planes that intersect in this layer. Deformation in a nanoscale multilayer structure provides a way to directly image the shearing process caused by dislocation movement.



September 2002


Farewell to Chris Boothroyd, who leaves for Singapore on 8 September.

Chris has been a member of this group for 20 years.



Many cakes were eaten on the occasion of Chris' departure.



August 2002

WELCOME to Nicola McKie and Anna Finlayson, who are both doing summer projects with us.

Nicola has just finished Part 1B Physics and is working on new phase unwrapping algorithms for electron holography.



Anna has just finished Part II Materials and is working on the characterisation of nanostructured magnetic materials using electron holography.



July 2002

CONGRATULATIONS to Paul Midgley on becoming Editor of Ultramicroscopy from September 2002.

Paul takes over from Pieter Kruit from Delft.



July 2002

CONGRATULATIONS to Angus Kirkland on being on being appointed to a staff position at the University of Oxford from January 2003.

Angus' research group (Rudi Meyer, Katherine Langley and Shery Chang) are moving with him.



July 2002

CONGRATULATIONS to Chris Boothroyd on being on being appointed to the position of Associate Principal Fellow at the Institute of Materials Research and Engineering in Singapore from 16 September, 2002.

Apart from brief visits to Japan, the USA and Singapore, Chris is leaving Cambridge for the first time since 1979.



June 2002

CONGRATULATIONS to Steffi Friedrichs on being awarded a Junior Research Fellowship at Hertford College, Oxford, from 1 October, 2002.



June 2002

Quantitative electron holography of biased semiconductor devices

A C Twitchett, R E Dunin-Borkowski and P A Midgley
Phys. Rev. Lett. 88 (2002), 238302.

The above paper, which describes the first application of electron holography to characterise the electrostatic potential in a semiconductor device as a current flows through it in the TEM, was published in Physical Review Letters on 10 June, 2002.

The figure on the right is a reconstructed phase image, which shows the electrostatic fringing field in the vacuum region outside a p-n junction in a 2V reverse biased cleaved wedge sample.

Click here to see the abstract of the paper on the journal website.
Click here to download the paper in pdf format [693 kB ].



May 2002

CONGRATULATIONS to Owen Saxton on being appointed to the position of Senior Tutor at New Hall, Cambridge, from 1 September, 2002.



May 2002

CONGRATULATIONS to Matthew Weyland on being awarded the Microbeam Analysis Society (MAS) Castaing Award for the best student paper presented at last year's MAS meeting. The paper was "Three Dimensional Energy Filtered Transmission Electron Microscopy" by Matthew Weyland and Paul Midgley.



April 2002

CONGRATULATIONS to Alison Twitchett on being awarded a Junior Research Fellowship at Newnham College, Cambridge, from January 2003.



April 2002

CONGRATULATIONS to Rudi Meyer on achieving a time of 3 hours 1 minute and 40 seconds in the London Marathon on April 14, 2002.



March 2002

CONGRATULATIONS to Joanne Etheridge on her appointment to a Senior Lectureship at Monash University, Melbourne.



February 2002

CONGRATULATIONS to Matthew Weyland on passing his Ph.D. viva. His thesis title was 'Two and three dimensional nanoscale analysis: new techniques and applications'.The examiners were Rik Brydson from Leeds and Chris Boothroyd.



January 2002

CONGRATULATIONS to Vicki Keast on her appointment to a Lectureship at the University of Sydney.



January 2002

James Loudon, Alex Porter and Alison Twitchett attend the Arizona State University winter school on high-resolution electron microscopy



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