The form of macroscopic physical property tensors of a crystalline structure can be determined from its magnetic or nonmagnetic point group symmetry. A ferroic crystal contains two or more equally stable domains of the same structure but of different spatial orientation. Macroscopic tensorial physical properties that are different in the domains provide a tensor distinction of the domains. The use of point group symmetries in this tensor distinction is reviewed in this chapter: Point group symmetry-based classifications of domains have been defined to determine if specific macroscopic tensorial physical properties can provide a tensor distinction of all or some domains that arise in a phase transition. For pairs of domains, the tensor distinction is determined from a point group symmetry relationship, called a twin law. Recent work on domain average engineering in ferroics that focuses on the averaged point group symmetry and averaged physical properties of subsets of domains is also discussed.
Online access to SPIE eBooks is limited to subscribing institutions.