Bi0.8Nd0.2FeO3: a new PbO-free antiferroelectric ceramic

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There are only a handful of functional oxides which exhibit antipolar cation displacements that can be fabricated at ambient pressures. Such compounds have either the NaNbO3 or PbZrO3 structure which differ in that the antipolar displacements are along the edges and face diagonals, respectively, of the pseudcocubic perovskite cell. Of these two structural types, only PbZrO3-based compounds, have ever shown the ability to switch between an antipolar (antiferroelectric) and polar (ferroelectric) states under electric field, giving rise to large strain and/or charge. The large polarisation and strain associated with PbZrO3 has resulted in its use as an end members in the solid solution PbZrO3 - PbTiO3 (PZT) which is the main functional ceramic system utilised for sensor and actuator applications. However, environmental legislation governing the fabrication of ceramics using PbO may well limit future markets for PZT. The discovery of a new PbO-free compound, Bi0.8Nd0.2FeO3, with the PbZrO3 structure is therefore extremely timely, of the utmost significance from a fundamental scientific perspective and could herald a new generation of PbO-free ceramics suitable for device applications. The proposal aims to understand the fundamental structure property relations of materials based on Bi0.8Nd0.2FeO3 and to develop ceramics suitable for device applications