Pyroelectric current measurements on PbZr0.2Ti0.8O3 epitaxial layers

Abstract

We report pyroelectric current measurements on 150 nm thick PbZr0.2Ti0.8O3 (PZT) epitaxial films using frequency-domain thermal measurements over the range 0.02 Hz–1.3 MHz. The measured pyroelectric currents are proportional to the rate of temperature change, from ∼10−5 A/m2 to ∼103 A/m2 over the range 10−2 to 106 K/s. The film temperature oscillation is controlled using either a hotplate, microfabricated heater, or modulated laser, and the pyroelectric current is measured from a microelectrode fabricated onto the film. The measured pyroelectric coefficient of the PZT films is nearly constant across the entire frequency range at ≈−200 μC/m2K.

Giant pyroelectric coefficient determined from the frequency dependence of the pyroelectric signal generated by epitaxial Pb(Zr0.2Ti0.8)O3 layers grown on single crystal SrTiO3 substrates

“…[14][15][16][17] In the experimental works, the pyroelectric coefficient was determined from the pyroelectric current measured at constant heating rate. 8,9,[18][19][20] In this Letter, we report on a different method for the estimation of the pyroelectric coefficient, using the frequency dependence of the pyroelectric signal measured in the voltage mode. A theoretical model developed by van der Ziel 21 was adapted to obtain the average temperature variation of the epitaxial pyroelectric layer of Pb(Zr 0.2 Ti 0.8 )O 3 (PZT) grown on a single crystal SrTiO 3 (STO) substrate with (001) orientation.…”

High-frequency thermal-electrical cycles for pyroelectric energy conversion

“…We characterized the temperature dependence of ferroelectric electric displacement by measuring the pyroelectric current from the device generated due to sinusoidal heating of the thin film. 30 Figure 2(b) shows the pyroelectric coefficient of the BaTiO 3 film measured as a function of out-ofplane electric field using a lock-in amplifier based 2x method. 30 A sinusoidal voltage at 1 kHz applied to the heater strip causes a temperature oscillation in the BaTiO 3 film at 2 kHz.…”

“…30 Figure 2(b) shows the pyroelectric coefficient of the BaTiO 3 film measured as a function of out-ofplane electric field using a lock-in amplifier based 2x method. 30 A sinusoidal voltage at 1 kHz applied to the heater strip causes a temperature oscillation in the BaTiO 3 film at 2 kHz. The temperature fluctuation generates pyroelectric current which was measured from the bottom electrode.…”

Direct Measurement of Pyroelectric and Electrocaloric Effects in Thin Films

“…Hence, any tertiary PEE [40] induced by temperature gradients in the film can be neglected and we can use the lumped parameter approach where the ferroelectric layer is considered to be isothermal at any instant. A similar approach [16] calculates θ F E using q H and works from the bottom of the substrate up to the ferroelectric layer. We, however chose to work from the top down so as to maximize the number of measured quantities in the model to compensate for any unideal deviation from theory.…”

“…[13] For all materials, but particularly for thin-film samples, measurement methods that can separate out deleterious or spurious signals are the key to accurately measuring the true pyroelectric nature. In turn, the work on thin films has turned to phase-sensitive pyroelectric measurement techniques, [14,15] including those based on microfabricated resistive heater-based measurements [16] and modulated laser-based approaches [17] to more accurately assess the pyroelectric response of these small volume samples.…”