The expressions for the spontaneous polar contribution δ n i s to the principal values of the refractive index due to the quadratic electro-optic effect in ferroelectrics have been considered within the phenomenological approach taking into account the polarization fluctuations. A method has been proposed for calculating the magnitude and temperature dependence of the root-mean-square fluctuations of the polarization (short-range local polar order) P sh = 〈 P fl 2 〉 1/2 below the ferroelectric transition temperature T c from temperature changes in the spontaneous polar contribution δ n i s ( T ) if the average spontaneous polarization P s = 〈 P 〉 characterizing the long-range order is determined from independent measurements (for example, from dielectric hysteresis loops). For the case of isotropic fluctuations, the proposed method has made it possible to calculate P sh and P s only from refractometric measurements. It has been shown that, upon interferometric measurements, the method developed in this work allows calculating P sh and P s directly from the measured temperature and electric-field changes in the relative optical path (the specific optical retardation) of the light.

In this work, a complex investigation of the film surface composition, chemical bonding, conductivity, optical properties, density, hardness and Young's modulus of ion-beam-modified polyimide films was carried out. It was shown that the partial destruction of chemical bonding under ion bombardment leads to the formation of graphite-like, amorphous carbon islands, which increase the surface film conductivity by several orders of magnitude, from an insulating to a semiconducting region. Strong enhancements of both the conductivity and the optical absorption coefficient occur when the fraction of amorphous carbon clusters dispersed in a polyimide matrix reaches 40%. The values of hardness, Young's modulus and density at high irradiation doses reach the values typical of a hydrogenated amorphous carbon.

This work is devoted to the ellipsometric investigation of the evolution of the molecular order in free standing films of the ferroelectric liquid crystalline compound M12/10 after its alignment by electric field. Creation of pronounced oscillations of anisotropic properties of films was found and monitored over a scale of hours. These oscillations are explained as the mutual precession of molecular directors.

Evolution of microhardness, internal stress and thickness of three types of carbon (a-C) films (#1–3) with predominantly sp2 bonds with different microhardness (H=60, 24 and 20 GPa) and density after annealing in air for 1 h at temperatures of 100, 200, 300, 350 and 400 °C was investigated. The stable behavior of these quantities up to 400 °C demonstrated only superhard films from set #1. The films from set #2 (H=24 GPa) showed the noticeable decrease in these values after annealing at 350 °C. The largest decrease of all the measured values after annealing at 350 °C showed the films from set #3. The films from series #2 and 3 fully vaporized after annealing at 400 °C. A considerable decrease has been observed not only in film thickness, but also in the density of films from set #3 after annealing at temperatures more than 300 °C, that indicates a modification of the film structure. Significant penetration of oxygen into film body without a loss of film thickness was observed in the range of 250–300 °C only for film #3. It was registered by the increase of resistivity, D band intensity in Raman spectra and sharp increase of the IR transmittance. Absorption bands at approximately 1750 and 1610 cm−1 which correspond to the vibrations of CO and CC appear in these IR spectra and simultaneously the G band in Raman spectra shifted to 1605 cm−1. The film obtained has a graphite-like structure and its composition corresponds approximately to formula CO0.15CO0.18. This structure is very unstable and very quickly vaporized starting from 350 °C.

In this work, determination of the refractive index profile and the optical gap E02 of PbZr1-XTiO3 thin films is described. Measurements were performed with the J. A Woollam spectral ellipsometer working on rotate analyzer mode. The temperature dependence of optical constants was obtained with a specially designed heating device.

In this work, the refractive index profile and the optical gap E-02 of PZT thin films was determined for the first time at elevated temperatures up to 500degreesC. Measurements were performed with J. A Woollam spectral ellipsometer working in rotate analyzer mode. To obtain the temperature dependence of optical constants, a specially constructed heating device was applied.

In order to increase the sensitivity to moisture uptake of polyimide (PI) and polyethersulfone films applied in bimorphic humidity sensors 50, 130 and 180 keV boron ions with irradiation doses between 1013 and 1016 B+/cm2 were implanted. A complex investigation of the following features has been carried out: chemical changes in the surface regions by attenuated total reflection–FTIR spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy (XPS); optical properties by spectroscopic ellipsometry; hardness and elastic modulus by depth-sensing low-load indentation technique; conductivity of modified polymer films. It could be shown, that the partial destruction of chemical bonding under ion bombardment leads to the creation of new amorphous and graphite-like structures, which increase the surface film conductivity by several orders of magnitude, and enhances the sensitivity of these polymer films to moisture uptake. The ion-beam irradiation destroys the anisotropic features of the refractive index of PI layers leading to its isotropization. Radiation-induced changes in the layer structure result in an increase of the hardness and elastic modulus of the modified layers up to ten and six times, respectively. The hardness and refractive index depth profiles were determined. The detectable effective modification depth estimated from the depth profiles is 250–300 nm at an ion energy of 50 keV and 400–450 nm at an ion energy of 180 keV.

In this work, a complex investigation of film composition, microstructure and physical properties of RF-sputtered self-polarized PZT thin films for IR sensor arrays was carried out. Hydrostatic stresses in Si substrates near edges of Pt/PZT microstructures were predicted theoretically by finite element calculations and measured by spatially resolved Raman spectroscopy. High hydrostatic stresses were obtained in patterned sensor pixels by Raman piezo-spectroscopy. The laser-intensity-modulation method was applied for the investigation of the self-polarization profile, whereas the depth profile of the refractive index was determined by means of spectroscopic ellipsometry. Polarization and refractive index profiles as well as interface stresses affect IR-radiation sensor performance. Thickness and area dependences of IR-radiation detector detectivity and noise equivalent temperature difference were calculated. The applications of self-polarized IR sensor arrays in presence detection and IR imaging are demonstrated.

This investigation deals with determination of optical parameters of thin PLZT films prepared by pulsed laser deposition on fused silica substrates at different oxygen pressure. Film composition and structure are investigated by WDX and XRD. Defects concentration in the films is studied using triboluminescence. Changes of film refractive index n((lambda) ), extinction k((lambda) ) with wavelength in the spectral region 0.3 - 1.1 micrometers and film thickness d are determined as a result of transmittance spectra processing. Waveguiding properties of the films are investigated.

Thin PLZT films of various stoichiometries have been prepared by laser deposition. Waveguiding and optical properties were characterised by prism coupling method, spectroscopic ellipsometry and by transmission measurements. The composition was determined by WDX. Changes of refractive index with wavelength are discussed.

Analytical calculations of polarization and optical refraction index in ferroelectric thin films are performed in the framework of thermodynamic theory. The solution of Euler-Lagrange equation with different extrapolation lengths delta(1) and delta(2) on different surfaces enables to obtain the thickness dependence of inhomogeneous polarization. The maximal polarization decreases with the decrease of film thickness. The dimensionless critical thickness l(1c) of thickness induced ferroelectric phase transition was expressed via extrapolation lengths and was shown to decrease from l(1c) = pi (delta(1) = delta(2) = 0) to l(c) = 0 (delta1(,) delta(2) --> infinity). The thickness dependence of the optical refraction index was found to be proportional to squared polarization. Refraction index and pyroelectric coefficient profiles were measured respectively by ellipsometry and LIMM methods in PbZr0,235Ti0,765O3 (PZT) thin films deposited onto Si/SiO2/ adhesion layer/(111) Pt substrate by RF sputtering. The comparison of the theory with observed refraction index profiles in PZT films with 1780, 1000 and 470 run as well as pyroelectric coefficient in the film 1000 nm had shown that the theory describes the main features of observed profiles and their thickness dependence.

The refractive index profile of PZT thin film perovskite/pyrochlore stacks was studied with a J. A. Woollam spectral ellipsometer. Evidence was found that self-polarization is determined by the interaction of perovskite sublayer with the bottom platinum electrode.

Ab initio energy structure calculations of pure KTaO3 (KTO) and KTaO3 doped with Li (KTL) were performed using the CASTEP code [M.C. Payne, M.P. Teter, D.C. Alan, T.A. Arias, and J.D. Joannopoulos, Rev. Mod. Phys. 64, 1045 (1992)] based on the density functional theory (DFT) and the intermediate neglect of the differential overlap INDO method. The optimized lattice parameters of perfect KTO calculated in this work are in a good agreement with the available experimental data. The population analysis shows that KTO has a mixed ionic-covalent type of bonds. DFT calculations for the KTL have been performed for a 2x2 x 2 supercell of KTO with one Li+ substituting K+. The Li+ off-center ion and nearest oxygen displacements are defined. It was shown that oxygen displacements around Li+ off-center ions lead to the production of two local states in the bandgap at 60 meV and 90 meV from the top of the valence band, which in all probability play an important role in the photostimulated processes.

Abstract In this work, we present new results of investigation of PbZr0.235Ti0.235O3 (PZT) films deposited onto Si/SiO2/ adhesion layer/(111) Pt substrate by RF sputtering. This paper continues and supplements our previous work reported in [1]. Both spectral ellipsometry and the laser-intensity-modulation method (LIMM) were used for thin film profiling. These two independent methods allow us to increase the accuracy of our investigation. Optical constants of PZT films, refraction index depth profile and polarization profile were determined.

Presented in this contribution are some observations of the stress evolution and degradations of diamond-like a-C, a-C:H and Ti-C:H (10–20 at.% of Ti) films deposited by magnetron sputtering of the C or Ti target in the Ar or Ar+CH4 gas mixture. The compressive stresses increased during several days for all the Ti-C:H films regardless of their structure (amorphous or a-C:H with TiC nanocrystalline inclusions) and composition (10–20 at.% of Ti). This phenomenon was not observed for a-C and was slightly displayed for a-C:H films having high hydrogen content. The growth of stress was accompanied by a decrease of optical constants, n and k. Simultaneously, Raman spectra and composition of Ti-C:H films remained unchanged. The degradation in ambient air during several hours or days takes place mostly for the films prepared by reactive sputtering in the Ar+CH4 gas mixture, while a-C films, sputtered from the C target in argon, demonstrated stable behavior despite their high compressive stress level.

Ab initio energy structure calculations of pure ${\mathrm{KTaO}}_{3}$ (KTO) and ${\mathrm{KTaO}}_{3}$ doped with Li (KTL) were performed using the CASTEP code [M.C. Payne, M.P. Teter, D.C. Alan, T.A. Arias, and J.D. Joannopoulos, Rev. Mod. Phys. 64, 1045 (1992)] based on the density functional theory (DFT) and the intermediate neglect of the differential overlap INDO method. The optimized lattice parameters of perfect KTO calculated in this work are in a good agreement with the available experimental data. The population analysis shows that KTO has a mixed ionic-covalent type of bonds. DFT calculations for the KTL have been performed for a $2\ifmmode\times\else\texttimes\fi{}2\ifmmode\times\else\texttimes\fi{}2$ supercell of KTO with one ${\mathrm{Li}}^{+}$ substituting ${\mathrm{K}}^{+}.$ The ${\mathrm{Li}}^{+}$ off-center ion and nearest oxygen displacements are defined. It was shown that oxygen displacements around ${\mathrm{Li}}^{+}$ off-center ions lead to the production of two local states in the bandgap at 60 meV and 90 meV from the top of the valence band, which in all probability play an important role in the photostimulated processes.

The 1.5-μm thick carbon films prepared by magnetron sputtering of a carbon target in Ar, Ar +CH4 and Ar+O2 gas mixtures show that the higher their intrinsic stress, the higher their microhardness and the lower their resistivity. The a-C films obtained without ion bombardment (unbiased; the mean free path of sputtered C atoms larger or equal to the cathode–anode distance) show microhardness up to 25 GPa. The biased a-C films (i.e. with ion bombardment) achieve the highest microhardness (up to 50 GPa) and the lowest resistivity (0.01 Ω cm). An increase in Ar pressure, or the optional addition of O2, results in a decrease in the microhardness and intrinsic stress and an increase in the film resistivity. In comparison to a-C films, by adding CH4 to Ar up to certain limit, the microhardness and intrinsic stress of these a-C:H films increase and subsequently decrease steeply. It was specified by analysis of the electron diffraction patterns of thin films (30–60 nm) deposited under the same conditions that the radius of the first co-ordination sphere of C atoms for all the films is in a good agreement with the value for graphite. The prime interplanar distance for biased a-C films is considerably lower than that for unbiased ones and for graphite. Our data indicate the sp2-bonded carbon structure of the deposited hard carbon films, in which the prime interplanar distance is reduced due to intrinsic stress. Thus, it is more suitable to explain the hardness origin as a consequence of the film nanostructure rather than the presence of sp3 bonds.

Investigations of PbZr0.235Ti0.765O3 (PZT) films of perovskite (pe) and pyrochlore(py) structure deposited onto Si/SiO2/ adhesion layer/(111) Pt substrate by RF sputtering were performed with J. A. Woollam spectral ellipsometer. Experimental data were compared with theoretical predictions.