Curie-temperature variation and microwave absorption in perovskites containing substitutional impurities

The investigation of dielectric properties provides an approach to the understanding of intra and inter molecular interactions, modes of motion and confirmational change in the macromolecules. It is well known that there are interesting temperature-dependent properties of ferroelectrics which results from the temperature-dependence of the low lying transverse optic mode of vibration i.e. soft mode.Lattice defect with substitutional impurities have a major influence on the static dielectric properties. The Curie-temperature and microwave losses are also affected by substitutional impurities. SrTiO3 (ST) is paraelectric above 37 K. The change in Curie-temperature can not be accounted for simply by considering change in lattice parameters or polarisability of the defect (impurity) ions.The temperature and defect dependence of dielectric loss in perovskites has been the subject of much interest due to their wide use in optical communication, memory display unit, temperature control devices and ceramic industry. Material Science Research India Vol. 7(2), 509-513 (2010)