Relaxor Ferroelectrics

It is interesting to note that as with almost all initial advances in the study of ferroelectric oxides the impetus for studies of relaxor ferroelectrics stemmed from early work on polycrystalline ceramic systems. In the case of the relaxor ferroelectrics, the advance originated from studies in Professor Smolensky’s group at the Ioffe Institute in Leningrad (now St. Petersburg) on perovskite structure electroceramics of complex composition. Originally classified as ferroelectrics with diffuse phase transitions, it slowly became clear that the very high dielectric maximum being highly dispersive could not mark a classical ferroelectric phase transition. Now, following studies at Penn State University, the suggested designation as relaxor ferroelectrics has become internationally adopted. The name is nicely compact and does highlight two key features, the combination of massive dielectric relaxation with almost classical lower-temperature ferroelectric response.