chapter  73
Pyroelectric Detectors
Pages 10

A crystal is considered to be pyroelectric if it exhibits a spontaneous temperature-dependent polarization. Of the 32 crystal classes, 21 are noncentrosymmetric, and 10 of these exhibit pyroelectric properties. Besides pyroelectric properties, all these materials exhibit some degree of piezoelectric properties as well-they generate an electric charge in response to mechanical stress.