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An amplification of near three orders of magnitude was observed in Pb(Zr,Ti)O3 (PZT) thin films deposited on Pt/Si substrates when the Si substrate is included as an impedance in series with the PZT capacitor. The effect is present only at wavelengths below 1100 nm, where the incident light can be absorbed in the Si substrate with generation of free carriers. These carriers in turns modulate the internal electric field inside the ferroelectric layer leading to a much larger variation of the polarization compared to the one generated only by the temperature variation. This fact leads to a considerable enhancement of the pyroelectric signal. The finding can be useful in designing pyroelectric detectors with enhanced characteristics for visible and near infrared region of the electromagnetic spectrum. [ABSTRACT FROM AUTHOR]

Abstract: The uniaxial stress dependence of the hysteresis behavior of ferroelectric films was studied. The DIFFOUR model was modified to include the uniaxial stress effect. Both the uniaxial stress and the external electric field were applied on the out-of-plane direction of the films. The polarization was measured with varying the magnitude of the applied stress and the electric field frequency via the dynamics of the polarization reversal in terms of hysteresis. The study was taken by means of Monte Carlo simulations using the spin-flip Metropolis algorithm. From the results, the district dependence of hysteresis behavior on frequency between low frequency and high frequency was prominent. On the other hand, the remanent and the coercivity significantly decreased with increasing applied stresses. Moreover, the areas under the hysteresis loops also decreased indicating smaller magnitude of energy dissipation. The results agree well with related experiments where applicable. [Copyright &y& Elsevier]

In this study, we characterized nano-structured Mn doped BST thin-films fabricated using a pulsed laser deposition process at the University of Houston, and PST thin-films fabricated using MOCVD at the Arizona State University. Coplanar waveguide test structures were used for experimental evaluation of the dielectric properties of the BST and PST thin-films fabricated on MgO and saphire substrates respectively. The test structures were fabricated on bare substrates as well as on the thin-film test samples for determination of attenuation and phase constants with and without the ferroelectric thin-films. The ε film for the Mn:BST film was approximately 1200 over the frequency range of 15–30 GHz with the loss-tangent averaging to 0.033. The PST thin-film on sapphire substrate had a zero-bias relative dielectric constant of 200 and the loss-tangent was estimated to be 0.05 over the measured frequency range of 10 to 18 GHz. [ABSTRACT FROM AUTHOR]