Quantifying Intrinsic, Extrinsic, Dielectric, and Secondary Pyroelectric Responses in PbZr_1–xTi_xO₃ Thin Films

Abstract

Applications such as solid-state waste-heat energy conversion, infrared sensing, and thermally-driven electron emission rely on pyroelectric materials (a subclass of dielectric piezoelectrics) which exhibit temperaturedependent changes in polarization. Although enhanced dielectric and piezoelectric responses are typically found at polarization instabilities such as temperature-and chemically induced phase boundaries, large pyroelectric effects have been primarily limited in study to temperature-induced phase boundaries. Here, we directly identify the magnitude and sign of the intrinsic, extrinsic, dielectric, and secondary pyroelectric contributions to the total pyroelectric response as a function of chemistry in thin films of the canonical ferroelectric PbZr 1−x Ti x O 3 (x = 0.40, 0.48, 0.60, and 0.80) across the morphotropic phase boundary. Using phase-sensitive frequency and applied dc-bias methods, the various pyroelectric contributions were measured. It is found that the total pyroelectric response decreases systematically as one moves from higher to lower titanium contents. This arises from a combination of decreasing intrinsic response (−232 to −97 μC m −2 K −1) and a sign inversion (+33 to −17 μC m −2 K −1) of the extrinsic contribution upon crossing the morphotropic phase boundary. Additionally, the measured secondary and dielectric contributions span between −70 and −29 and 10−115 μC m −2 K −1 under applied fields, respectively, following closely trends in the piezoelectric and dielectric susceptibility. These findings and methodologies provide novel insights into the understudied realm of pyroelectric response.

Strain‐Driven Mixed‐Phase Domain Architectures and Topological Transitions in Pb1−xSrxTiO3 Thin Films

“…Thus far we have demonstrated an exacting and extensive pathway to control domain structures in ferroelectrics. This is of particular interest since it is well known that domain structures can greatly impact the evolution of properties (e.g., dielectric, [ 75,76 ] piezoelectric, [ 77 ] and pyroelectric [ 23,78 ] ) in ferroelectrics. To study the effect of our ability to continually manipulate the domain structures on the properties, the dielectric constant (ε r ) was measured (Experimental Section).…”

“…[ 20 ] Finally, other similar chemistry‐controlled ferroelectric heterostructures have shown rich property modulation such as unique hysteresis response, [ 21 ] temperature‐stable dielectric permittivity, [ 22 ] and enhanced pyroelectric properties. [ 23 ]…”

Beyond Expectation: Advanced Materials Design, Synthesis, and Processing to Enable Novel Ferroelectric Properties and Applications

“…Such approaches are shedding new light on this relatively understudied realm of physics in ferroelectric oxides. Free from convoluting effects of spurious, thermally stimulated currents which have long plagued previous characterization approaches for thin films, the "true" pyroelectricity can now be measured accurately in capacitor structures that are compatible with thin films and are providing robust insights into previously neglected effects such as dielectric and extrinsic domainwall contributions to pyroelectricity [84,85]. Furthermore, with today's thin-film processing strategies like the aforementioned defect engineering, greater electric fields and temperatures may be applied at increasing frequenciesgoing well beyond what can be physically obtained in bulk materials [66] and thus improving the pyroelectric performance.…”

A Simple Numerical Method for Evaluating Heat Dissipation from Curved Wires with Periodic Applied Heating

“…1,2 One of the most reliable and widely used techniques to measure thermal conductivity, the three-omega method, involves periodic Joule heating of a metal wire fabricated on the material of interest. [3][4][5][6][7][8][9][10][11][12] Heating frequencies are chosen such that the thermal wave emitted by the wire penetrates only a few hundred microns into the substrate before dissipating. The rapid dissipation of the thermal wave confines the volume of the sample being probed by the experiment, thereby increasing the measurement's sensitivity to thermal signals from thin films and interfaces near the sample's surface, while simultaneously minimizing the effects of convective and radiative heat loss.…”