Temperature dependence of conventional and effective pyroelectric coefficients for compositionally graded BaxSr1−xTiO3 films

Ferroelectric thin films (∼1.2 μm) of BaxSr1−xTiO3 with gradients in composition normal to the growth surface were formed on platinum substrates by metalorganic decomposition. Effective (pseudo) pyroelectric coefficients as large as 0.06 μC/cm2 K have been obtained from these active ferroelectric devices under the application of an ac field (charge pumping). In contrast, a value of only −0.003 μC/cm2 K has been measured for the conventional pyroelectric coefficient.