Magnetism, Electronic Properties and Ferroelectricity in Heavy Metal Pyrochlores

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Metals from the transition series in the Periodic Table - such as iron, manganese and nickel often have unpaired electrons in their compounds and this leads some of their most interesting properties such as colour, magnetism and electrical conductivity. Heavy metals from the transition metal series include platinum, tungsten and the oxides of these elements show similar useful properties. The aim of this project is to prepare oxides of these heavy transition metals - where the transition metal is in combination with a second metals such as calcium or cadmium - and study their electronic and magnetic properties. One structure type, or arrangement of the metal and oxide ions, will be studied namely the pyrochlore structure which is also known for a naturally occuring mineral of this name. The pyrochlore structure type has been poorly studied for these heavy transition metals but where known shows some fascinating properties such as superconductivity (zero resistance to the flow of electrons)at low temperature and transitions between insulating behaviour and high electrical conductivity when the materials is heated or cooled. Once materials have been synthesised (using a variety of techniques including reactions under high pressures - replicating reaction conditions found in nature) they will be studied in terms of their structures and physical properties. Through this work we intend to develop a complete understanding of how composition (e.g. which heavy metal type), structure (the exact arrangement of the metal and oxide ions in the pyrochlore structure)and physical properties are related. With this information we will be understand how to produce new materials with potential useful applications in electronic, sensor and data storage systems.