I am a senior scientist at ISIS, conducting a research program in condensed matter physics, and with responsibility for developing techniques and software to study dynamics in single crystals.
Research and development interests
My scientific research revolves around strongly correlated electron materials. These are systems where the behaviour of the electrons cannot be understood as arising from their motion in an average field due to all the other electrons, but instead depends on the subtle interplay of the spin, charge, orbital and lattice degrees of freedom in the materials. In consequence, the materials can display unexpected ground states with unusual physical properties, properties which in turn can be extremely sensitive to externally applied stimuli such as a magnetic field. It is for these reasons that the study of strongly correlated electron systems is a major theme in condensed matter research. I have a long-running programme studying colossal magnetoresistive manganese oxides, quantum fluctuations in one and two dimensional model magnets, and the spin fluctuations in elemental ferromagnets. In addition, I have also been a member of teams studying iron based and copper oxide high transition temperature superconductors. Highlights from my research and key publications are given further down.
Neutron instrumentation and techniques
Most of my scientific work has been carried out at the ISIS spallation neutron source, where I performed experiments which demonstrated that inelastic neutron scattering from single crystals could be performed highly effectively at pulsed sources, and I was instrumental in establishing the use of time-of-flight techniques with single crystals as a routine probe of magnetic dynamics. I was responsible for the scientific specification and commissioning of the MAPS spectrometer at ISIS, the first time-of-flight neutron spectrometer optimised for measuring excitations in single crystals, and which has been the template for the design of numerous instruments since built at ISIS and other neutron facilities. Over the past few years my efforts have concentrated on maximising the information that can be obtained from the data collected on such instruments through the development of techniques and software to fully map magnetic and lattice dynamics in all four dimensions of wave-vector and energy (http://horace.isis.rl.ac.uk, ), as well as software that uses distributed computing to optimise parameters in user-supplied models of the dynamics that fully accounts for the instrumental resolution function (http://tobyfit.isis.rl.ac.uk).
Excitations software home page: click here
Web pages for software projects:
Visualising and analysing multi-dimensional neutron data: Horace
Fitting of resolution broadened models to data: Tobyfit
Grants, awards, teaching and other activities
Honorary Professor of Physics, London Centre for Nanotechnology, University College London, 2007 – present.
Recipient of the 2003 Willis Prize of the Institute of Physics Neutron Scattering Group.
Colossal magnetoresistive (CMR) manganites. My early work includes the first determination of the spin wave spectrum throughout the Brillouin zone of a CMR manganite , the observation of short-range antiferromagnetic fluctuations coexisting with ferromagnetic critical fluctuations , and the demonstration of atomic scale stacking of spin valves in a layered manganite . My current interest in colossal magnetoresistive manganites centres on studying the excitations in charge-ordered materials to test the existence or otherwise of magnetic dimers known as Zener polarons .
Quantum magnetism and model magnetic systems in one and two dimensions. Highlights in quantum magnetism include the study of spinons and magnetic form factor in the spin ½ Heisenberg antiferromagnetic chain [4,6], as well as being part of the team that first showed the unambiguous existence of spinons in the Heisenberg antiferromagnet . My current work in quantum magnetism includes attempting to apply quantum information concepts to one-dimensional systems.
Itinerant electron ferromagnetism of the elemental transition metals. My renewed interest in the spin dynamics of itinerant electron ferromagnets stems from the development of techniques and software for complete mapping of the dynamics, but the goal of making measurements in these canonical magnets to compare with ab initio calculations dates from the very start of my career .
High temperature superconductivity. I have also been part of long-standing collaborations studying spin dynamics in high transition temperature superconductors. As well my more recent work in studies of the high energy spin dynamics of parents of iron based superconductors [3,5], in earlier years I was a key member of the experimental team in several seminal papers on cuprate superconductors [7,8,10,12].
 “HORACE: software for the analysis of data from single crystal spectroscopy experiments at time-of-flight neutron instruments”
R.A. Ewings, A. Buts, M.D. Le, J. van Duijn, I. Bustinduy, T.G. Perring
Nucl. Instrum. Methods. Phys. Res. Sect. A 834, 132 (2016)
 “Ground State in a Half-Doped Manganite Distinguished by Neutron Spectroscopy”
G.E. Johnstone, T.G. Perring, O. Sikora, D. Prabhakaran, A.T. Boothroyd
Phys. Rev. Lett., 109 237202 (2012)
 “Itinerant spin excitations in SrFe2As2 measured by inelastic neutron scattering”
R.A. Ewings, T.G. Perring, J. Gillett, S.D. Das, S. E. Sebastian, A.E. Taylor, T.Guidi, A.T. Boothroyd,
Phys. Rev. B 83 214519 (2011)
 “Effect of covalent bonding on magnetism and the missing neutron intensity in copper oxide compounds”