Emeritus Professor Denis Greig

Colleagues will be sorry to learn of the death, on 5 September 2022, of Emeritus Professor Denis Greig, former Professor of Physics.  The following tribute has been contributed by his friend and colleague, Professor Bryan Hickey.

Denis Greig began his career in Physics as an undergraduate at Dundee, then part of the University of St Andrews.  He went on to Aberdeen to do a PhD which began his work in the field of Solid State Physics.  Denis was studying the low temperature properties of semiconductors, but in order to do so he had to build his own liquefier to obtain cryogenic liquids to achieve the necessary low temperatures.  This was thought to be so dangerous that Denis spent his time working in a shed a safe distance away from the heart of the University.  Following his PhD Denis took up a postdoctoral fellowship at the National Research Council of Canada which was then a world-leading centre for low temperature physics. He returned to the UK to follow his career, arriving in Leeds in 1960 where he was interviewed by Professor Edmund Stoner, who asked him, among other things, which page of the Times he read first; of course Denis said “the sports pages”.  Apparently the ‘right’ answer was the leader followed by the letters page – but he got the job nonetheless.

Over the 37 years that Denis officially worked at the University he had very broad research interests.  He worked on the thermal properties of polymers and the electrical properties of a new class of materials called amorphous or glassy metals.  These are highly disordered states of matter that require rapid cooling from the liquid state to a solid state at a rate of a million degrees a second.  Denis was part of the team who designed and built machines in our workshops known as melt spinners due to the required cooling being achieved by splattering molten metal on to a rapidly rotating copper wheel.

At about this time Denis became very interested in the electronic properties of materials that could be revealed by extracting electrons using high intensity light (photoemission) that could be obtained at synchrotrons such as Daresbury and the ESRF in Grenoble.  He published a huge volume of work in collaboration with the theoretician Prof Jim Matthew at York and started what is now one of the principal research themes of the group: working at large scale facilities to use the scattering of neutrons, photons, electrons and muons to reveal the behaviour of new states of matter.

A transformation in the research direction of the Condensed Matter Group happened in 1988 when Denis was invited to apply for a new type of deposition system utilising Molecular Beam Epitaxy (MBE) to create ultrathin (only a few atoms thick) layers of crystalline metals.  Denis won the competition and the new machine arrived in Leeds in 1989, initiating what is now an internationally recognised hallmark of the Condensed Matter group in Leeds – growing ultrathin materials by bespoke methods to discover new and exploitable properties.  The original MBE had one growth chamber and could produce one sample per day. Now we have several machines that can produce 24 samples per day and a new ultra-high vacuum growth system with four interconnected chambers. After 32 years of service we are retiring the original MBE system this year.

Although Denis officially retired in 1997, he never really stopped doing Physics.  Sometime in 2007 Denis suffered a problem with his eye – he developed a defect in his retina known as a macular hole.  His treatment was in the form of surgery where a gas bubble was injected through the iris into the eye, following which he had to remain face-downwards for about a week.  But Denis could see the bubble in his eye and to alleviate the boredom he began tracking and measuring the progress of the bubble.  Following conversations with his consultant, Mr WH Woon of St James’s, they published the results.  It transpired that though this technique worked, the reasons why a macular hole develops and why operations were successful were unclear and this had hampered the development of macular hole surgery.  Joined by Prof M Savage, a fluid mechanics expert, they obtained a ‘discipline hopping’ grant from the MRC to assess the physical mechanisms of the gas bubble treatment of patients with macular holes.  This was hands-on research and once a fortnight Denis would visit the abattoir and return with a bag of porcine eyeballs, and they were free!  With encouraging results the group published a further six papers on the mechanical properties of the gel, sclera and retinal tissue measured by a variety of techniques including atomic force microscopy.

Denis was skilled with his hands too. He inherited his love of woodworking from his father and attended evening classes nearly every year whilst living in Leeds, not to learn more, but to use their superior tools to complete his many well-crafted projects.  Most of us in the group have received a gift of Denis’s handiwork, cots and wheelbarrows for the children, and if you were lucky, a piece of furniture.  Denis’s woodworking legacy lives on in the Physics department and the University too – it was he who made the leader-boards for the annual prizes in Physics and Astronomy which now adorn the wall of the new Bragg Building.  The oak staves carried by the procession-leading ushers and the mace bearer’s attendant at every graduation ceremony in the University of Leeds are the handiwork and gift of Denis Greig, gentleman, master joiner and Professor of Physics.