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The results of the structure and dielectric characteristics studies of the Ba2NdFeNb4O15/Sr0.6Ba0.4Nb2O6/SrRuO3/MgO(001) multilayer heterostructure are presented. Nano-sized films of multiferroic Ba2NdFeNb4O15, ferroelectric Sr0.6Ba0.4Nb2O6, and conductive SrRuO3 were deposited by RF cathode sputtering in an oxygen atmosphere in separate sputtering units. It was established that all layers of the heterostructure were grown as single-crystals and had a high structural perfection. The degradation of the ferroelectric parameters of the heterostructure was practically not detected up to 1010 switching cycles, while they were characterized by high energy efficiency. [ABSTRACT FROM AUTHOR]

Phase composition, nanostructure and properties of Sr0.6Ba0.4Nb2O6/Ba2NdFeNb4O15/Si(001) heterostructures have been studied by X-ray diffraction, scanning probe microscopy, and dielectric spectroscopy. Sr0.6Ba0.4Nb2O6 and Ba2NdFeNb4O15 films were fabricated under identical conditions by RF cathode sputtering in an oxygen atmosphere. It was shown that the obtained heterostructures were pure, the Sr0.6Ba0.4Nb2O6 and Ba2NdFeNb4O15 layers were polycrystalline textured, and the layer thickness did not affect the unit cell strain. The heterostructure exhibited a ferroelectric-like response, but the polarized regions arising under the application of electric field were unstable at room temperature. The reasons for the identified regularities are discussed. [ABSTRACT FROM AUTHOR]

Structure, surface morphology, and magnetic properties of Sr0.6Ba0.4Nb2O6 film and BiFeO3/Sr0.6Ba0.4Nb2O6 heterostructures with different BiFeO3 thicknesses were studied. The heterostructures were fabricated by RF-cathode sputtering on a SrRuO3/MgO(001) substrate. According to X-ray diffraction data for BiFeO3/Sr0.6Ba0.4Nb2O6/SrRuO3/MgO(001), the BiFeO3 layer had a tensile strain of the unit cell up to 0.43%. Atomic force microscopy showed that the surface of the heterostructures had a low roughness and was represented by growth blocks, the average size of which did not exceed 91 nm. The results of magnetic force microscopy showed a clear magnetic response in BiFeO3/Sr0.6Ba0.4Nb2O6/SrRuO3/MgO(001) heterostructures for 30-150 nm thick BiFeO3 layer. [ABSTRACT FROM AUTHOR]

The phase composition, structure, and optical properties of the BiFeO3/SrTiO3/Al2O3 (c-cut) heterostructure have been studied using XRD analysis, spectrophotometry, and multi-angle ellipsometry. BFO/STO/A12O3 heterostructures have been obtained by high-frequency cathode sputtering in an oxygen atmosphere using the intermittent deposition technology. It was found that the BiFeO3 and SrTiO3 layers grew with an orientation in the direction of the [111] crystallographic axis parallel to the normal to the Al2O3 substrate. It has been shown that the damaged layer on the surface of the heterostructure does not exceed 2‒3 nm, and no signs of the presence of boundary layers at the Al2O3–SrTiO3 and SrTiO3–BiFeO3 interfaces have been identified. The dispersion dependences of the refractive indices of BFO and STO layers are calculated. The reasons for the revealed regularities are discussed. [ABSTRACT FROM AUTHOR]

Using the RF cathode sputtering method, ferroelectric films of barium-strontium niobate Sr0.5Ba0.5Nb2O6 were synthesized on a semiconductor substrate. Their phase composition, crystal structure, nanostructure, dielectric, and ferroelectric characteristics were studied. The temperature ranges of phase transformations, the characteristic values of spontaneous polarization and coercive fields, the magnitude and nature of the change in the imaginary and real parts of the complex permittivity in the temperature range −190 ÷ 250 °C were established in the films. The reasons for the revealed regularities are discussed. [ABSTRACT FROM AUTHOR]

Single-phase, impurity-free barium neodymium ferroniobate (Ba2NdFeNb4O15) films ~660 nm in thickness have been grown on a Pt(001)/MgO(001) substrate using rf cathode sputtering in an oxygen atmosphere. According to X-ray diffraction data, the films are c-axis-oriented. Two phase transformations have been identified in the Ba2NdFeNb4O15 films in the temperature range from –190 to 200°C: paraelectric → ferroelectric and ferroelectric → ferroelectric. The Ba2NdFeNb4O15 films have been shown to have high room-temperature energy efficiency. The mechanisms underlying the observed effects are discussed and potential applications of barium neodymium ferroniobate nanofilms are analyzed. [ABSTRACT FROM AUTHOR]

Thin polycrystalline lead zirconate titanate (PZT) films with a Zr:Ti ratio close to morphotropic phase boundary were obtained by radiofrequency sputtering at a temperature of 540 °C on a metal substrate, and their structural and electrophysical properties were studied. The piezoelectric coefficient, remnant polarization, coercive field, and dielectric constant of the PZT film are 3.84 μC/cm2, 1.20 ÷ 1.26 μC/cm2, 1.1 ÷ 1.3·105 V/cm, and 145, respectively. Domains of the perovskite phase are located on the surface of the film protrusions. The magnitude of the piezoelectric modulus of the domain is 17.9 ÷ 22.4 pC/V. [ABSTRACT FROM AUTHOR]

Barium strontium niobate films have been grown on MgO(001) substrates by single-step rf cathode sputtering of a ceramic target with the stoichiometric composition Sr0.5Ba0.5Nb2O6 in an oxygen atmosphere under various conditions (at different substrate biases). It has been shown that, depending on its polarity, the substrate bias either increases or reduces the flux of structure-forming elements to the substrate and, as a consequence, changes the growth rate, without impairing the surface morphology or surface perfection of the film or producing impurity phases. The mechanisms underlying the observed general relationships are discussed. [ABSTRACT FROM AUTHOR]

Metal–ferroelectric–semiconductor Pb(ZrTi)O3/Ba0.2Sr0.8TiО3/Si(001) heterostructures have been synthesized by radiofrequency cathode sputtering. It has been established that the Pb(ZrTi)O3 films are single-phase and textured and the degree of predominance of one crystallographic orientation over another (110 or 001) is determined by the Ba0.2Sr0.8TiO3 sublayer thickness. It is shown that, by varying the sublayer thickness and/or the amplitude of one period of the external bipolar field effect, one can obtain different electric states of the structure, which can give rise to creating memory cells, including multilevel ones. [ABSTRACT FROM AUTHOR]

Barium strontium niobate films ~300 nm in thickness have been grown on MgO(001) substrates by rf sputtering of a ceramic target with the stoichiometric composition Sr0.5Ba0.5Nb2O6 (SBN50) in an oxygen atmosphere. Composition–depth profiles across the films have been measured using secondary ion mass spectrometry, and we have determined their phase composition, structure, and c cell parameter in the temperature range 20–500°C. The results demonstrate that the SBN50 films are heteroepitaxial and have two crystallographic orientations with an angle of ~36.8° between them and identical tetragonal cell parameters (а = 12.438 Å and с = 3.955 Å). Their chemical composition does not vary in the thickness direction and corresponds to the composition of the ceramic target. The SBN50 films have a higher temperature of the ferroelectric-to-paraelectric phase transition than do SBN50 single crystals and polycrystalline films, and their thermal expansion coefficient changes sign near 100°C. [ABSTRACT FROM AUTHOR]

Thin films of sodium niobate (NaNbO3) on a MgO(001) substrate with a predeposited SrRuO3 layer were obtained for the first time by the method of RF cathode sputtering in an oxygen atmosphere. X‑ray diffraction data showed the obtained films to be single-phase and single-crystalline. The parameters of the unit cells of NaNbO3 and SrRuO3 layers in the tetragonal approximation were found to be = 0.3940(1) nm, = 0.389(1) nm, = 0.4004(1) nm, and = 0.392(3) nm. Misfit strain of the unit cell of NaNbO3 amounted to ε33 = 0.007 and ε11 = 0.002. The results of dielectric and piezoelectric measurements showed that the films occurred in a ferroelectric state. [ABSTRACT FROM AUTHOR]

The structure and optical characteristics of thin films of relaxor ferroelectric Ba0.5Sr0.5Nb2O6 grown by RF sputtering in an oxygen atmosphere on an Al2O3 substrate (c cut) have been studied. X-ray diffraction analysis shows that Ba0.5Sr0.5Nb2O6 films are c-oriented and unit-cell parameter c is 3.948(1) Å. Ellipsometric measurements confirm that SBN-50 films are characterized by a natural growth direction, which coincides with the direction of the optical crystal axis. An analysis of ellipsometric results shows that there is no transition layer at the film/substrate interface; the damaged layer on the free film surface is 7.5 nm thick, and the volume filling factor is estimated to be 0.625. [ABSTRACT FROM AUTHOR]

Sr0.5Ba0.5Nb2O6 (SBN) relaxor ferroelectric films of different thicknesses have been grown on Pt(111)/Si(001) substrates by rf sputtering. We have studied their structure, composition–depth profiles, lattice dynamics, and dielectric properties at temperatures from 25 to 200°C. The results demonstrate that the composition of the films does not vary with depth and corresponds to that of the ceramic target used and that the SBN/Pt interface has a transition layer more than 30 nm in thickness, consisting of a mixture of platinum and SBN. According to X-ray diffraction characterization results, the films are polycrystalline, with a preferential orientation of the SBN [001] axis along the normal to the substrate surface. At a film thickness of 950 nm or above, the SBN films on Pt(111)/Si substrates differ insignificantly in unit-cell parameters, lattice dynamics, and Burns temperature from SBN single crystals. We discuss general relationships of structure formation and characteristics of the films. [ABSTRACT FROM AUTHOR]

The paper presents the results of characterization of the crystal structure, microstructure, dielectric and piezoelectric properties of PbFe 0.5 Nb 0.5 O 3 ceramics modified at the stage of synthesis by lithium carbonate. Due to a detailed analysis of relaxation processes and piezoelectric activity in the region of the ferroelectric to paraelectric state transition, conclusions are drawn about the optimal concentration of the modifier as well as, from the standpoint of mass production technology, the prospects for using such ceramics as targets for producing single-phase thin films of lead ferroniobate on Si substrates as part of a one-stage method of high-frequency cathodic deposition in O 2 atmosphere are shown. The features of the formation of C (U) dependences and the fatigue effect, which are manifested during cyclic field action on the obtained heterostructures, were studied. Image 1 • The Vogel-Fulcher type dielectric relaxation with a half a degree width was detected. • Piezoelectric activity of PFNL ceramics is retained above T C. • Single-phase polycrystalline textured PFN films on Si substrates were obtained. • The fatigue effects of the PFN film began to appear only after 107 switching cycles. [ABSTRACT FROM AUTHOR]