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RESEARCH PRODUCT

<title>Glass to ferroelectric phase transition induced by ac electric field in PbMg<formula><inf><roman>1/3</roman></inf></formula>Nb<formula><inf><roman>2/3</roman></inf></formula>O<formula><inf><roman>3</roman></inf></formula> thin films</title>

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The nonlinear dielectric response of epitaxial heterostructures of relaxor ferroelectric PbMg1/3Nb2/3O3 thin films was experimentally studied using digital Fourier analysis. The amplitudes and the phase angles of the dielectric harmonics were determined as a function of temperature and the amplitude of the sinusoidal ac field. The response of the films was reconstructed assuming a linear contribution of the film-electrode interface capacitance. In the films at low amplitudes of ac field, a glass-like behavior was identified by a maximum in the third-order nonlinear dielectric permittivity around the freezing temperature, accompanied by a square field dependence of the amplitudes of the odd harmonics and the absence of the even-order harmonics. With increasing amplitude of ac field, a glass-to-ferroelectric transition was indicated by a deviation from the square field dependence of the amplitudes of the odd harmonics, the appearance of the even-order harmonics, and the switching of the phase angle of the third harmonic to 90°. Such an unstable glassy behavior was suggested to originate due to the presence of interfaces, crystallographic strain, and nanometer-scale structural features.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.