Pyroelectric properties of polydomain epitaxial Pb(Zr1−x,Tix)O3thin films

Abstract

The pyroelectric properties of polydomain epitaxial Pb(Zr${}_{1\ensuremath{-}x}$,Ti${}_{x}$)O${}_{3}$ thin films are investigated using a Ginzburg--Landau--Devonshire thermodynamic model. We explore the three major contributions to pyroelectric response in thin films, including intrinsic effects and previously neglected contributions such as extrinsic and secondary effects, to provide a complete picture of pyroelectric property development. The pyroelectric coefficient for epitaxial thin films is calculated as a function of strain, temperature, and composition for 0.5 \ensuremath{\leqslant} $x$ \ensuremath{\leqslant} 1.0. We find that structural transitions driven by epitaxial strain can greatly enhance the pyroelectric coefficient and that extrinsic contributions due to temperature-driven domain wall motion can significantly alter the intrinsic pyroelectric properties. Furthermore, we show that the pyroelectric coefficient at room temperature is maximized at the multicritical point between various polydomain phases and is also consistently high along the boundary between the c/a/c/a and ${a}_{1}$/${a}_{2}$/${a}_{1}$/${a}_{2}$ polydomain phases. Additionally, we have investigated the impact of epitaxial strain on pyroelectric response in polydomain states and found that the extrinsic contribution from domain walls to the pyroelectric coefficient varies depending on the sign of the strain. Finally, we examine the addition of secondary contributions to pyroelectricity that arise from thermal expansion in materials and provide insight into the effect of this contribution on the overall magnitude of response.