Relaxor features in ferroelectric superlattices: A Maxwell-Wagner approach

A Maxwell-Wagner series capacitor model is proposed to explain anomalous di electric properties of ferroelectric superlattices. The results of the mode l show that a superlattice consisting of normal ferroelectric layers separa ted by low-resistivity interfacial regions can account for most experimenta l results reported to date, namely: dielectric enhancement for certain stac king periodicities, giant permittivities, and temperature migration of diel ectric maxima as a function of frequency. The predictions of the model are discussed and compared to our own experimental results from thin film super lattice capacitors made by pulsed-laser deposition. (C) 2000 American Insti tute of Physics. [S0003-6951(00)05345-6].