Effects of composition ofPbTiO3on optical properties of(1−x)

Abstract

Thin films of (1Ϫx)PbMg 1/3 Nb 2/3 O 3 -xPbTiO 3 ͑PMN-PT͒ with xϭ0, 0.1, 0.3, 0.35, and 0.4 have been fabricated on ͑001͒MgO single-crystal substrates by pulsed laser deposition ͑PLD͒. X-ray diffraction ͑XRD͒, scanning electron microscopy ͑SEM͒, and atomic force microscopy ͑AFM͒ were employed to characterize the structural properties of these PMN-PT films. Our results show that these films possess excellent structural properties and are cube-on-cube grown on ͑001͒MgO substrates. Spectroellipsometry ͑SE͒ was used to characterize the depth profiles, the microstructural inhomogeneities, including void and surface roughness, refractive indices and extinction coefficients of the films. In the analysis of the measured SE spectra, a double-layer Lorentz model with four oscillators was adopted to represent the optical properties of the PMN-PT films. In this model, the films were assumed to consist of two layers-a bottom bulk PMN-PT layer and a surface layer composed of bulk PMN-PT as well as void. Good agreement was obtained between the measured spectra and the model calculations. The film thickness measured by SEM is consistent with that obtained by SE while the root mean square ͑rms͒ surface roughness determined by AFM is also close to our fitted effective surface layer thickness obtained by SE. Our measurements show that the refractive indices of the PMN-PT films increase with PbTiO 3 contents. This dependence is consistent with our optical transmittance measurements which revealed that the energy band gaps of PMN-PT films decrease with increasing PbTiO 3 contents. The correlation between the energy band gap and the refractive index is discussed.

Dielectric behaviors of relaxor ferroelectric Pb(Mg1/2Nb1/2)O3–35% PbTiO3: temperature and frequency dependences

“…4(a) is drawn by Eqs. (11) and (13) with the parameters derived out before. We find that there are peaks in the curves and the maxima of ε 1 increase with decreasing frequencies.…”

“…The differences between the PMN-35 % PT and PMN-10 % PT are that the PMN-35 % PT has a monoclinic phase [11] and also a clean rhombohedral phase in the low temperature [12]. And a higher PT content leads to a reduced band gap [13]. Therefore, it is necessary to examine whether the Cheng et al's model is only a special case, or it can describe the characteristics of RFE in a wider range.…”

Highly (111)-oriented and pyrochlore-free PMN–PT thin films derived from a modified sol–gel process

“…Over the past few decades, ferroelectric thin films ((1 − x) Pb(Mg 1/3 Nb 2/3 )O 3 -xPbTiO 3 , PMN-PT) have received special attention due to many fascinating properties such as their large electric-optic coefficients, longitudinal coupling coefficients, piezoelectric constants and high dielectric constants coupled with low loss [1][2][3]. It had been proven to be promising materials for high-k capacitors, actuators and non-linear optical devices [4,5].…”

Effects of growth temperature on structure and electrical properties of dielectric (Ba,Sr)TiO3 capacitors with transparent conducting oxide electrodes

“…The BST/ZIO/STO films grown at 550, 650, and 750 • C had mean optical transmittances of 74.5, 71.3, and 64.5%, respectively, in the visible wavelength regions. Changes in electronic structure due to crystal quality may be responsible for variations in the optical properties of BST thin films [24]. The rough film surface and many micro-defects in the BST film grown at 750 • C might be responsible for its serious decrease in optical quality.…”