PMN–PT based relaxor ferroelectrics as very smart materials

The basic classification of smart materials and structures is reviewed briefly. The role of nonlinear response for achieving field-tunability of properties is described in simple terms. The observation of the two-way shape-memory effect in a solid solution of lead magnesium niobate (PMN) and lead titanate (PT) for the nominal atomic composition 65:35 is reported. Possible factors influencing the occurrence of the two-way effect are discussed. It is argued that such relaxor ferroelectric ceramics can function as smart materials (rather than serving merely as components of smart structures), because they can meet the “information-reduction” criterion. And they qualify to be called very smart because they have a fairly large number of smartness attributes, including the two-way shape-memory attribute reported here.