Loveday is considered one of the pioneers of neutron diffraction at high pressure and was a founder member of the Paris–Edinburgh high-pressure neutron diffraction collaboration. His specialism is in techniques for high-pressure neutron scattering and examining the application of these techniques for investigating structures and transitions in planetary ices, hydrates, water and other simple molecular systems. He is the author of more than seventy papers and his work on the behaviour of clathrate hydrates at high pressure and their relevance to models of planetary bodies including Titan was published in Nature and has been highly cited.