Novel Ferroic Materials with Functionally active Domain Walls

Some functional materials, such as ferroelectrics, contain membrane or sheet structures called "domain walls". For decades, domain walls were dismissed as being minor microstructural components of little significance. It is now clear that nothing could be further from the truth. Domain walls often, in fact, have unique functional properties that are completely different from the domains that they surround: they can be conductors or superconductors when the rest of the material is insulating; they can display magnetic order in non-magnetic crystals and they can possess aligned electrical dipoles when the matrix surrounding them is non-polar. In effect, domain walls represent a new class of sheet-like nanoscale functional material.

The aim is to 1) synthesis and characterise novel ferroic materials with potentially exciting domain structures; and 2) to tune domain wall properties in new and existing materials be appropriate chemical modification (doping). The project will involve: (solid state) synthetic work, including ceramic processing; crystallographic structure determination using both x-ray and neutron diffraction; and electrical characterization using a range of techniques such as dielectric and impedance spectroscopy, polarization-field and thermally stimulated depolarization current measurements.