Dielectric properties in low and high frequencies of oxynitride layered perovskite compounds

For many years, perovskite materials have been studied regarding the wide variety of their properties achieved by substitutions on A and B cations-sites in the basic ABO3 structure. Moreover, by replacing nitrogen for oxygen,... [ view full abstract ]

For many years, perovskite materials have been studied regarding the wide variety of their properties achieved by substitutions on A and B cations-sites in the basic ABO₃ structure. Moreover, by replacing nitrogen for oxygen, oxynitride perovskite compounds were also synthesized. They present original properties compared to their parent oxides, such as an absorption in the visible region resulting in colored materials with potential applications in the fields of visible light-driven photocatalysis and pigments. Since recently, attention has been focused on their dielectric properties; high permittivity values ranging from some tens to several thousands have been reported on ceramics and thin films. The dielectric and ferroelectric behavior of perovskite oxynitrides is currently the subject of many studies; a relaxor-type ferroelectric behavior has been proposed, which would originate from an O/N order in the perovskite structure. The purpose of the present contribution is to present an overview of the dielectric and ferroelectric properties of oxynitride perovskite compounds. It will be illustrated by our own results on oxynitride perovskite films such as LaTiO₂N, SrTaO₂N and (Sr_1-xLa_x)(Ta_1-xTi_x)O₂N solid solution. This will include dielectric and ferroelectric measurements in macro and nano scales, in low and high frequencies and versus electric field and temperature.