Concepts and recent advancements in perovskite metal oxides

The development of new kinds of materials with hybrid properties can be linked to human activities. The human brain resembles an electronic circuit, the human eye resembles a smart sensor, and the human arm resembles actuators. Among the different types of materials, perovskites are a class of materials with structures related to that of the mineral perovskite, calcium titanate (CaTiO3), having the general formula ABO3. The A and B site atoms are cations and sit at the corner and body center of the cubic structure, respectively. These materials have been intensively studied since the middle of the 20th century because of their various properties, such as dielectric, piezoelectric, pyroelectric, ferroelectric, magnetic, superconductive, and multiferroic. The properties of perovskite materials are greatly affected by the structure and composition with suitable ions. The structure–property relationships in connection with the tolerance factor play a vital role in predicting the properties. This chapter focuses on the basic concept behind the properties of perovskite materials by examining the structure–property relationships. Some of the material applications are explained.