Study of the pyroelectric behavior of BaTi1−xSnxO3 piezo-ceramics

In this work, the thermal square wave method at single-frequency (TSWM) was applied to functionally graded BaTi1−x Sn x O3 samples with a tin gradient of 0.075 ≤ x ≤ 0.15. The samples were fabricated by sintering of bi-, tri- and tetramorph green bodies. The polarization at the back side with a higher tin content was in opposite direction to the polarization of the surface with a lower tin content. This was attributed to the appearance of a space charge layer. The determined depth profiles of the pyroelectric coefficient illustrate the appearance of a nearly constant polarization in the region of lower tin concentration of tri- and tetramorph samples. The pyroelectric coefficient profiles were in good agreement with the averaged over sample thickness pyroelectric coefficient obtained separately by the quasistatic method.