Fundamentals of design and creation of heteroepitaxial structures of perovskite materials for instrument
The dependence of the concentration of lead and calcium Raman spectra (RS) films of lead titanate-calcium Pb1-xCaxTiO3 (PCT), it is determined that the substitution of Pb Ca on the general nature of the spectra does not change even when x = 0.45 Raman spectra correspond to tetragonal ferroelectric phase, which is implemented in pure PCT. It was revealed that the soft mode component A1(TO) in the film-lanthanum titanate lead Pb0.9La0.1TiO3 (PLT) has a frequency of 280 cm-1 and significantly shifted to lower frequencies with an increase in the content of La. This increases the interaction of the modes with low frequency 180 cm-1 mode, the frequency of which is reduced by only 10 cm-1 for x = 0.45. The obtained Raman spectra of ceramics and films of PLT can be concluded that the substitution of Pb for La has a significant impact on the bond Ti-O.
It is found that the stress relaxation mechanism dislocation occurs in the calcium-lead titanate having contact with the substrate when the thickness of the transition layer is about 1.3 nm. Using electron diffraction was determined and the film substrate disorientation in the direction perpendicular to the film plane, that is from 0,5° to 1,0°, that is within the error, and consistent with the data of X-ray analysis.
The connection between the conditions, of the crystallization, of the films and their structural, and deformation characteristics. Found generalized energy parameter characterizing the totality of elementary processes: spraying and transfer of the material particles through the plasma HF discharge, their condensation on the substrate. A method for the quantitative determination of the generalized power parameter identifies areas of change that correspond to the qualitative and quantitative changes in the mechanism of formation of the films. A method for determining the internal parameters, which allowed to reduce the problem of obtaining multiparameter complex oxides, a phase diagram analysis, which greatly simplified the preparation of films with desired properties, and opened the way for the creation of the new technology. The resulting method of determining the internal parameters heteroepitaxy layers simplify the preparation of films with desired properties.
The method of construction according to the CVC discharge optical emission spectroscopy, which allows to establish unequivocally identical discharge parameters by using different compositions of target or changing the configuration of the electrodes of the spray device. Carry out the separation of different types of high-frequency discharge for internal parameters, while optimizing the film growing conditions properly take into account the role of plasma processes in the overall process of their growth.
The temperature dependence of the unit cell parameters PCT and PLT films on a substrate made of magnesium oxide oriented parallel to the crystallographic axis Z(001) on which a layer of Pt/MgO platinum were obtained heteroepitaxy structures of these materials. The temperature dependence, of the polarized Raman spectra, of the films, of lanthanum titanate-lead. It is noticed that with increasing temperature, the intensity of all polar modes decreases, and the frequency of the soft mode E(TO) is increased from 60 cm-1 at room temperature and up to 72 cm-1 at 368 K.
It revealed that the heteroepitaxy films of lead lanthanum titanate on a substrate obtained PLT Pt/MgO, oriented parallel to the crystallographic axis Z(001), there are two-dimensional stresses that lead to the formation of 180-degree c-domain structure in the tetragonal phase, which plays an important role in the low-temperature phase transitions.