Research Guides

The synthesis, structures, chemistry and physical properties of new solids.

Our aim is to synthesise new solid state compounds and correlate their chemical and physical properties with their compositions and crystal structures. Many technological developments are driven by the discovery of solids with particular magnetic, electronic or chemical properties. The compounds we make may also be desirable model materials with which to test theories in condensed matter physics.

We work on non-oxide or multi-anion compounds which offer contrasting and complementary properties to the better-studied oxides. We synthesise new compounds using a range of methods, measure their crystal structures and physical properties and feed the results back into the synthetic programme.

Versatility in metal oxychalcogenides

Members of an homologous series of layered oxychalcogenides in which transition metal oxide layers are separated by metal sulfide layers exhibit unusual magnetic properties and are also of interest as potential Li-ion battery materials. In particular we are investigating new magnetic and electronic states in these compounds in a collaboration with Oxford Physics supported by the Engineering and Physical Sciences Research Council.

Iron-based superconductors

New high temperature superconductors based on iron arsenide, phosphide or selenide layers were discovered serendipitously in 2007/8. These compounds are still relatively poorly understood. We have been engaged in a vigorous collaboration with colleagues in Oxford Physics to make new examples of these materials and understand their physical properties, and are currently investigating possible applications of some of these in technology in collaboration with the Centre for Applied Superconductivity led by the Oxford Materials department.

Further details of these and other projects may be found in the research section of the group's webpages

"Layered CeSO and LiCeSO Oxide Chalcogenides Obtained via Topotactic Oxidative and Reductive Transformations"
Cassidy, S. J.; Pitcher, M. J.; Lim, J. J. K.; Hadermann, J.; Allen, J. P.; Watson, G. W.; Britto, S.; Chong, E. J.; Free, D. G.; Grey, C. P.; Clarke, S. J. Inorg. Chem., 2019, 58, 3838–3850

"Synthesis, structure and properties of the layered oxide chalcogenides Sr2CuO2Cu2S2 and Sr2CuO2Cu2Se2"
Blandy, J. N.; Smura, C. F.; Liu, S.; Cassidy, S. J.; Woodruff, D. N.; McGrady, J. E.; Clarke, S. J. Inorg. Chem., 2018, 57, 15379-15388

"Complex magnetic ordering in the oxide selenide Sr2Fe3Se2O3S"
Cassidy, S. J.; Orlandi, F.; Manuel, P.; Hadermann, J.; Scrimshire, A.; Bingham, P. A.; Clarke, S. J. Inorg. Chem., 2018, 57, 10312-10322

"Synthesis and Magnetic Structure of the Layered Manganese Oxide Selenide Sr2MnO2Ag1.5Se2"
Blandy, J. N.; Boskovic, J. C.; Clarke, S. J. J. Solid State Chem. 2017, 245, 61.

"Complex microstructure and magnetism in polymorphic CaFeSeO"
Cassidy, S. J.; Batuk, M.; Batuk, D.; Hadermann, J.; Woodruff, D. N.; Thompson, A. L.; Clarke, S. J. Inorg. Chem. 2016, 55, 10714

"The Parent Li(OH)FeSe Phase of Lithium Iron Hydroxide Selenide Superconductors."
Woodruff, D. N.; Schild, F.; Topping, C. V.; Cassidy, S. J.; Blandy, J. N.; Blundell, S. J.; Thompson, A. L.; Clarke, S. J. Inorg. Chem. 2016, 55, 9886.

"Soft chemical control of the crystal and magnetic structure of a layered mixed valent manganite oxide sulfide."
Blandy, J. N.; Abakumov, A. M.; Christensen, K. E.; Hadermann, J.; Adamson, P.; Cassidy, S. J.; Ramos, S.;  Free, D. G.; Cohen, H.; Woodruff, D. N.; Thompson, A. L.; Clarke, S. J. APL Materials. 2015, 3, 041520.

"Soft chemical control of superconductivity in lithium iron selenide hydroxides Li1–xFex(OH)Fe1–ySe."
Sun, H.; Woodruff, D. N.; Cassidy, S. J.; Allcroft, G. M.; Sedlmaier, S. J.; Thompson, A. L.; Bingham, P. A.; Forder, S. D.; Cartenet, S.; Mary, N.; Ramos, S.; Foronda, F. R.; Williams, B. H.; Li, X.; Blundell, S. J.; Clarke, S. J. Inorg. Chem. 2015, 54, 1958.

"Ammonia-rich high temperature superconducting intercalates of iron selenide revealed through time-resolved in-situ X-ray and neutron diffraction."
Sedlmaier, S. J.; Cassidy, S. J.; Morris, R.; Drakopoulos, M.; Reinhard, C.; Moorhouse, S. J.; O'Hare, D.; Manuel, P.; Khalyavin, D.; Clarke, S. J. J. Am. Chem. Soc. 2014 136, 630-633.

"Enhancement of the superconducting transition temperature of FeSe by intercalation of a molecular spacer layer."
Burrard-Lucas, M.; Free, D. G.; Sedlmaier, S. J.; Wright, J. D.; Cassidy, S. J.; Hara, Y.; Corkett, A. J.; Lancaster, T.; Baker, P. J.; Blundell, S. J.; Clarke, S. J. Nature Materials 2013, 12, 15-19.