The physics of pyroelectric detectors is reviewed, including a discussion of response and electronic noise and their dependence on device design and material parameters Other sources of noise are described, particularly as generated by environmental effects such as microphony, together with techniques for their minimisation The range of ferroelectric materials which have been assessed for use in pyroelectric detectors is reviewed and their properties compared, particularly from the aspect of application to different types of devices Finally, an account is given of the wide range of applications for which pyroelectric detectors have been used, including a detailed description of both the pyroelectric vidicon and pyroelectric arrays and their application to thermal imagers

https://iopscience.iop.org/article/10.1088/0034-4885/49/12/002/pdf

Pyroelectric devices and materials

Correlation between microstructure, strain behavior, and acoustic emission of soft PZT ceramics

TeO2 glass of purity exceeding 98.5 mol.% has been made, despite earlier suggestions that some 7.5–10 mol.% of modifier is required to form vitreous telluride networks. It is argued that in view of the high purity of the glass obtained, TeO2 may well be able to form glass by itself, given an appropriate thermal history in preparation. The hydrostatic and uniaxial pressure dependences of ultrasonic waves propagated in this glass at room temperature have been measured. The results provide the second and third order elastic constants of the glass. The bulk modulus is consistent with a ring diameter averaging about 8 atoms (Te4O4 rings) suggesting that the glass is a disordered version of paratellurite; however, if the TeO bending force constant were to be unusually strong, then a larger ring diameter (as in tellurite) would be indicated. Although the anion coordination number is only 4, the pressure derivatives of the second order elastic constants are positive and the third order elastic constants are negative, in marked contrast to the anomalous behaviour of silica-based glasses. These findings suggest that bond bending motions of bridging atoms between the trigonal bypyramidal groups (which are the structural units) do not play an important role in the elastic properties of TeO2 glass. In consequence the shear and oongitudinal acoustic mode Gruneisen parameters are both positive (γ1 = +2.14, γs = +1.11): the long wavelength acoustic modes stiffen under hydrostatic pressure.

E.F Lambson

Papers

An apparatus for high precision measurements of ultrasonic wave velocity

Acoustic emission from domain wall motion in ferroelectric lead germanate

A threshold electric field for acoustic emission from ferroelectric Pb5Ge3O11