Pyroelectricity and Thermal Expansion

The total pyroelectric response at constant stress, p , is the sum of the primary pyroelectic response, given by p, and the secondary pyroelectric response, which is the product of the direct piezoelectric stress coefficient gs, and the thermal expansion coefficients  

The pyroelectric coefficient at constant strain, p is expressed by the polarization model, using the quasi-harmonic approximation, as 

2 as a function of temperature. Primary pyroelectricity accounts for about 9% of the total response of the crystal at 300 K. The temperature dependence of secondary pyroelectricity is significant and determined by that of the thermal expansion coefficients. 

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Table 7.17 Material coefficients of PVDF polymer thin film (Nalwa 1995). Elastic constants and compliances, piezoelectric, pyroelectric and thermal expansion coefficients are listed.

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