Donald McKenzie Paul will be remembered by many who worked with him as a brilliant scientist. Beneath a gruff exterior lay a cheerful, friendly, no-nonsense Scot from Kingskettle, Fife. Don worked in the Department of Physics, University of Warwick from 1984 until his death in 2019. After his first degree at St Andrews, Don completed his PhD in low-temperature physics investigating the de Haas-van Alphen effect in metals, under the supervision of Professor Mike Springford at the University of Sussex. Don then moved to a post-doctoral position at the University of Edinburgh working in the field of neutron scattering with Professor Roger Cowley. Neutron scattering would dominate his research work for the next 40 years.

Don moved to France in 1980 to take up an instrument scientist post at the Institut Laue Langevin (ILL), Grenoble, before returning to the UK in 1984 for a ‘New Blood’ Lectureship in the Department of Physics at Warwick. He initially joined the Nuclear Magnetic Resonance Group as Professor Eddie Seymour who headed the group was keen for Don to get involved in NMR. Don, however, had other ideas and quickly secured research grants to work on superconductors and itinerant ferromagnets. He kept his neutron scattering work, collaborating with colleagues at the ILL and would frequently escape to perform experiments there, which he absolutely loved - and so the Superconductivity and Magnetism Group led by Don was established.

With the discovery of the high-temperature superconductors in 1986, the pace of work quickened and the group expanded with an influx of funds from EPSRC Rolling Grants and generous support from the Department. The excellent research of the Superconductivity and Magnetism Group continued to build Warwick’s reputation for condensed matter physics. Don’s prolific publication record and high profile activities including the pioneering use of Small Angle Neutron Scattering to examine the vortex state of superconductors gained him widespread recognition. In 1992 he was promoted directly from Lecturer to a Professor, a rarity at the time. In recognition of his work, Don was awarded the prestigious Mott Prize for Condensed Matter Physics from the Institute of Physics in 1996.

Whilst his efforts at Warwick were producing great results in the field of superconductivity and magnetism, he was also heavily involved in developing instrumentation and improving techniques for experiments at neutron sources. He led a project to design, build, and commission a new instrument called MAPS on the ISIS neutron facility at the Rutherford Appleton Laboratory, the first in a new generation of spectrometers that has changed the way the neutron scattering community thinks about inelastic neutron scattering. Throughout his career he was very closely associated with all the decision making bodies at the large scale facilities and held positions at ENSA, STFC and the IOP/RSC Neutron Scattering group. Later in his career, Don’s interests turned to the use of muons to probe the vortex state of superconductors and then more recently negative muons to investigate archaeological artefacts such as coins, jewellery, and weapons.

Don has supervised many PhD students, and those who were extremely able and capable of independent work thrived - those who were not often chose a new career path after year 1! He has inspired many students to stay in science and they continue to visit the group. As a teacher he enjoyed delivering lectures, however, his exam questions were often unfathomable to many students and he never understood why. His tutorial sessions were also rather unconventional - he would choose a topic or a problem at random and enjoy getting students to work things through in steps on the board. This of course excited the ablest students, and frightened the rest! Don always relished an intellectual challenge and one could rely on him to help solve any physics problem - a skill that was sorely missed while he was ill. He was also the go-to person for computer hardware and software problems and for many years he maintained all of the group’s computers, as well as writing programs for data analysis.

Don’s career was cruelly interrupted by bouts of poor health, and despite soldiering on very bravely for many years he was never able to fully recover. Don was a unique and multi-talented scientist, who was great fun to work with. At the height of his career he was one of the UK’s finest experimental condensed matter physicists. He will be fondly remembered and sorely missed not just by us at Warwick, but by the wider scientific community.