I am a scientist with the ISIS Excitations and Polarised Neutrons Group, and I am co-responsible for the MERLIN spectrometer.
Research and development interests
After several years working at synchrotrons, I have recently changed to become a neutron scientist to take advantage of neutron scattering for the study of strongly correlated electron systems. My particular interests lie in the magnetic properties of f-electron systems and transition metal oxides, particularly multiferroics and 5d systems.
Selected recent publications
H. C. Walker, F. Fabrizi, L. Paolasini, F. de Bergevin, D. Prabhakaran, A. T. Boothroyd, and D. F. McMorrow Circularly polarized x-ray scattering investigation of spin-lattice coupling in TbMnO3 in crossed electric and magnetic fields Phys. Rev. B 88, 214415 (2013)
S. Boseggia, R. Springell, H. C. Walker, H. M. Ronnow, Ch. Rüegg, H. Okabe, M. Isobe, R. S. Perry, S. P. Collins and D. F. McMorrow Robustness of basal-plane antiferromagnetic order and the Jeff=1/2 state to structural distortions in single-layer spin-orbit Mott insulators Phys. Rev. Lett. 110, 117207 (2013)
T. Klimczuk, H. C. Walker, R. Springell, A. B. Shick, A. H. Hill, P. Gaczynski, K. Gofryk, S. A. J. Kimber, C. Ritter, E. Colineau, J.-C. Griveau, D. Bouxière, R. Eloirdi, R. J. Cava, R. Caciuffo, Negative thermal expansion and antiferromagnetism in the actinide oxypnictide NpFeAsO Phys. Rev. B 85, 174506 (2012)
F. de Bergevin, L. Paolasini, H. Walker, A. Boothroyd, F. Fabrizi, D. Prabhakaran & D. McMorrow Illuminating the magnetism of multiferroics by polarised X-rays Notiziario Neutroni e Luce di Sincrotrone 17, 10 (2012)
H. C. Walker, F. Fabrizi, L. Paolasini, F. de Bergevin, J. Herrero-Martin, A. T. Boothroyd, D. Prabhakaran & D. F. McMorrow Femtoscale magnetically induced lattice distortions in multiferroic TbMnO3 Science 333, 1273 (2011)
H. C. Walker, R. Caciuffo, D. Aoki, F. Bourdarot, G. H. Lander and J. Flouquet Resonant X-ray Scattering Study of the URu2Si2 Hidden-order Phase Phys. Rev. B 83, 193102 (2011)
F. Fabrizi, H. C. Walker, L. Paolasini, F. de Bergevin, T. Fennell, N. Rogado, R. J. Cava, Th. Wolf, M. Kenzelmann, and D. F. McMorrow Electric field control of multiferroic domains in Ni3V2O8 imaged by x-ray polarization-enhanced topography Phys. Rev. B 82, 024434 (2010)
F. Fabrizi, H. C. Walker, L. Paolasini, F. de Bergevin, A. T. Boothroyd, D. Prabhakaran, and D. F. McMorrow Circularly Polarized X-Rays as a Probe of Noncollinear Magnetic Order in Multiferroic TbMnO3 Phys. Rev. Lett. 102, 237205 (2009)