Solid solution samples of the three-component system (1 − x)Pb(Ti0.5Zr0.5)O3−xCdNb2O6 with x = 0.0125–0.0500, Δx = 0.0125 were obtained by solid phase synthesis followed by sintering using conventional ceramic technology. The crystal structure, microstructure, electrophysical, and thermophysical properties of these ceramics have been studied. It is shown that all studied solid solutions can be divided into two groups (with x = 0.0125 and with x> 0.0125), characterized by different characteristics of the change in properties with variations in external influences. This is probably due to the transition from a perovskite-type structure with a tetragonal (T) unit cell to inhomogeneous solid solutions consisting of a series of T-phases with similar cell parameters. A conclusion is made about the expediency of using the data obtained in the development of similar materials for devices based on them.Solid solution samples of the three-component system (1 − x)Pb(Ti0.5Zr0.5)O3−xCdNb2O6 with x = 0.0125–0.0500, Δx = 0.0125 were obtained by solid phase synthesis followed by sintering using conventional ceramic technology. The crystal structure, microstructure, electrophysical, and thermophysical properties of these ceramics have been studied. It is shown that all studied solid solutions can be divided into two groups (with x = 0.0125 and with x> 0.0125), characterized by different characteristics of the change in properties with variations in external influences. This is probably due to the transition from a perovskite-type structure with a tetragonal (T) unit cell to inhomogeneous solid solutions consisting of a series of T-phases with similar cell parameters. A conclusion is made about the expediency of using the data obtained in the development of similar materials for devices based on them.

Considering the advantages of high Curie temperature and environment-friendly nature of KNN piezoelectric ceramics, the limitation of weak piezoelectric response and their temperature sensitivity to applications is worth exploring. Herein, the textured (1-x)(K0.5Na0.5)(Nb0.96Sb0.04)O3-x(Bi0.5Na0.5)HfO3(x = 0.01−0.045) lead-free ceramics were synthesized by templated grain-growth method. The high piezoelectric performance (d33 of 474 pC/N and strain of 0.21%) and excellent temperature stability (unipolar strain maintained within 4.3% change between 30∘C and 165∘C) were simultaneously achieved in the textured KNNS-0.03BNH ceramics. The high piezoelectric performance can be attributed to the summation of the crystallographic anisotropy and phase structure contributions in textured ceramics. The superior temperature stability of piezoelectric properties can be interpreted by the contribution of crystal anisotropy to piezoelectric properties reduces the effect of phase transition on piezoelectric properties deterioration. This study provides an effective strategy for simultaneously achieving high piezoelectric properties and superior temperature stability in KNN-based textured ceramics.Considering the advantages of high Curie temperature and environment-friendly nature of KNN piezoelectric ceramics, the limitation of weak piezoelectric response and their temperature sensitivity to applications is worth exploring. Herein, the textured (1-x)(K0.5Na0.5)(Nb0.96Sb0.04)O3-x(Bi0.5Na0.5)HfO3(x = 0.01−0.045) lead-free ceramics were synthesized by templated grain-growth method. The high piezoelectric performance (d33 of 474 pC/N and strain of 0.21%) and excellent temperature stability (unipolar strain maintained within 4.3% change between 30∘C and 165∘C) were simultaneously achieved in the textured KNNS-0.03BNH ceramics. The high piezoelectric performance can be attributed to the summation of the crystallographic anisotropy and phase structure contributions in textured ceramics. The superior temperature stability of piezoelectric properties can be interpreted by the contribution of crystal anisotropy to piezoelectric properties reduces the effect of phase transition on piezoelectric properties deterioration. This study provides an effective strategy for simultaneously achieving high piezoelectric properties and superior temperature stability in KNN-based textured ceramics.

This work promotes the room temperature energy storage properties of the multiferroics. In this approach, impacts of PrFeO3 doping on PT-based solid solutions (Pb1−xPrxTi1−xFexO3, x = 0.21, 0.22, 0.23, 0.24, 0.25 and 0.26) have been explored. X-ray diffraction (XRD) patterns were used to estimate the crystallographic parameters, confirming the single phase tetragonal structure. The ferroelectric Curie temperature (TcFE) is observed to drop from 410 K to below room temperature as the Pr concentration increases. The ferroelectric P-E loops were used to determine the energy storage values at room temperature. The sample x = 0.24 achieved the maximum value of energy storage density of 362.25 mJ/cm3 with the efficiency of 40.5%. The ferroelectric P-E loops were used to determine the energy storage values at room temperature. The validity of magnetoelectric coupling in all samples was confirmed by magneto-dielectric studies and found that the sample x = 0.24 shows the maximum response with the coupling coefficient (γ) = 15.54 g2/emu2.This work promotes the room temperature energy storage properties of the multiferroics. In this approach, impacts of PrFeO3 doping on PT-based solid solutions (Pb1−xPrxTi1−xFexO3, x = 0.21, 0.22, 0.23, 0.24, 0.25 and 0.26) have been explored. X-ray diffraction (XRD) patterns were used to estimate the crystallographic parameters, confirming the single phase tetragonal structure. The ferroelectric Curie temperature (TcFE) is observed to drop from 410 K to below room temperature as the Pr concentration increases. The ferroelectric P-E loops were used to determine the energy storage values at room temperature. The sample x = 0.24 achieved the maximum value of energy storage density of 362.25 mJ/cm3 with the efficiency of 40.5%. The ferroelectric P-E loops were used to determine the energy storage values at room temperature. The validity of magnetoelectric coupling in all samples was confirmed by magneto-dielectric studies and found that the sample x = 0.24 shows the maximum response with the coupling coefficient (γ) = 15.54 g2/emu2.

The (1−x)(0.94Bi0.5Na0.5TiO3–0.06BaTiO 3)–xKTaO3(BNBT–xKT) lead-free ferroelectric ceramics were produced using the traditional solid-state sintering technique, and the phase structure, surface morphology, electrical properties were all thoroughly examined. Every ceramic has a single perovskite structure and there is no second phase, as shown by the XRD patterns and Raman spectra. Scanning electron microscopy revealed that all samples displayed dense microstructure and cubic grain. In addition, KT encourages grain growth due to the oxygen vacancies induced by doping or volatilization of ions at high temperatures. The Tmof the ceramics decreases with increasing doping levels due to oxygen vacancies acting as dipoles upon the addition of KT, and the dielectric loss of all samples is low at ambient temperature. In comparison to the pure BNBT ceramic’s bipolar strain value of 0.12%, the BNBT–2KT ceramic achieved a maximum bipolar strain of ∼0.506% and unipolar strain of ∼ 0.430% with the corresponding d33*up to 538 pm/V under 80 kV/cm field. Performance significantly improved as a result of this. A test of the correlation between temperature and ferroelectric properties shows that the largest strain value of the BNBT–2KT ceramic occurs at ambient temperature and that the phase change from ferroelectric to relaxor is complete. Additionally, it is discovered that the BNBT–3KT ceramic can sustain a stable strain across a broad temperature range, suggesting that it has good temperature stability. The aforementioned findings demonstrate that lead-based ceramics may be replaced with BNBT–xKT ceramics.The (1−x)(0.94Bi0.5Na0.5TiO3–0.06BaTiO 3)–xKTaO3(BNBT–xKT) lead-free ferroelectric ceramics were produced using the traditional solid-state sintering technique, and the phase structure, surface morphology, electrical properties were all thoroughly examined. Every ceramic has a single perovskite structure and there is no second phase, as shown by the XRD patterns and Raman spectra. Scanning electron microscopy revealed that all samples displayed dense microstructure and cubic grain. In addition, KT encourages grain growth due to the oxygen vacancies induced by doping or volatilization of ions at high temperatures. The Tmof the ceramics decreases with increasing doping levels due to oxygen vacancies acting as dipoles upon the addition of KT, and the dielectric loss of all samples is low at ambient temperature. In comparison to the pure BNBT ceramic’s bipolar strain value of 0.12%, the BNBT–2KT ceramic achieved a maximum bipolar strain of ∼0.506% and unipolar strain of ∼ 0.430% with the corresponding d33*up to 538 pm/V under 80 kV/cm field. Performance significantly improved as a result of this. A test of the correlation between temperature and ferroelectric properties shows that the largest strain value of the BNBT–2KT ceramic occurs at ambient temperature and that the phase change from ferroelectric to relaxor is complete. Additionally, it is discovered that the BNBT–3KT ceramic can sustain a stable strain across a broad temperature range, suggesting that it has good temperature stability. The aforementioned findings demonstrate that lead-based ceramics may be replaced with BNBT–xKT ceramics.

To solve the problem of directional arrangement of small template particles, we designed a lamination technique for the preparation of dense ceramics with high texture degree based on the phase-field simulation. Referring to the experimental data, the initial microstructures of the template and matrix layers were constructed. The effect of the average length of template on the coarsening behavior of the template layer was investigated in detail. The results suggested that there was a stable stage in the growth process of template grains, which would be conducive to the densification of textured ceramics. This phenomenon has been confirmed by corresponding experiments. In addition, we demonstrated a critical thickness of matrix layer for the preparation of highly textured ceramics by using the template with various average lengths. The grain size of highly textured ceramics could be controlled by adjusting the template size and thickness of matrix layer.To solve the problem of directional arrangement of small template particles, we designed a lamination technique for the preparation of dense ceramics with high texture degree based on the phase-field simulation. Referring to the experimental data, the initial microstructures of the template and matrix layers were constructed. The effect of the average length of template on the coarsening behavior of the template layer was investigated in detail. The results suggested that there was a stable stage in the growth process of template grains, which would be conducive to the densification of textured ceramics. This phenomenon has been confirmed by corresponding experiments. In addition, we demonstrated a critical thickness of matrix layer for the preparation of highly textured ceramics by using the template with various average lengths. The grain size of highly textured ceramics could be controlled by adjusting the template size and thickness of matrix layer.

A method for obtaining a new type of surface acoustic wave (SAW) transducer operating at double frequency with a single-phase closed-loop lattice and a piezoelectric zinc oxide film is developed and experimentally investigated. A method for calculating such a transducer has been developed, its equivalent circuit has been compiled, taking into account propagation losses, losses in the metal film and the inductance of the connecting wires. When the frequency is doubled, the SAW attenuation per unit length increases.A method for obtaining a new type of surface acoustic wave (SAW) transducer operating at double frequency with a single-phase closed-loop lattice and a piezoelectric zinc oxide film is developed and experimentally investigated. A method for calculating such a transducer has been developed, its equivalent circuit has been compiled, taking into account propagation losses, losses in the metal film and the inductance of the connecting wires. When the frequency is doubled, the SAW attenuation per unit length increases.

Epitaxial VO2 films grown by pulsed laser deposition (PLD) method with superior phase transition related switching characteristics are successfully embedded to SAW devices using concept of the “impedance loaded SAW sensor”. A resistance of VO2 sensor abruptly drops from 0.7 MΩ to 90 Ω when it is heated above ∼65∘C and shows a narrow hysteresis loops when switching. Two designs of SAW devices are examined in which RF signal is reflected back from interdigital transducer (IDT) or a surface acoustic waves (SAW) is transferred through a coupler and the RF response is altered 2 and 3 times correspondingly upon the phase transition in VO2. In the proposed devices with external load, a SAW does not propagate via VO2 film and therefore is not attenuated which is beneficiary for wireless applications. Additionally, a SAW phase shift as great as 50∘ is induced to the SAW transferred through the coupler due to the phase transition in VO2. The proposed approach may boost the development of remotely controlled autonomous sensors, including those based on VO2 metamaterials and hybrid plasmonic structures for near IR/middle IR and sub-THz/THz applications.Epitaxial VO2 films grown by pulsed laser deposition (PLD) method with superior phase transition related switching characteristics are successfully embedded to SAW devices using concept of the “impedance loaded SAW sensor”. A resistance of VO2 sensor abruptly drops from 0.7 MΩ to 90 Ω when it is heated above ∼65∘C and shows a narrow hysteresis loops when switching. Two designs of SAW devices are examined in which RF signal is reflected back from interdigital transducer (IDT) or a surface acoustic waves (SAW) is transferred through a coupler and the RF response is altered 2 and 3 times correspondingly upon the phase transition in VO2. In the proposed devices with external load, a SAW does not propagate via VO2 film and therefore is not attenuated which is beneficiary for wireless applications. Additionally, a SAW phase shift as great as 50∘ is induced to the SAW transferred through the coupler due to the phase transition in VO2. The proposed approach may boost the development of remotely controlled autonomous sensors, including those based on VO2 metamaterials and hybrid plasmonic structures for near IR/middle IR and sub-THz/THz applications.

The present investigations mainly focused on the colossal dielectric response and complex impedance analysis of LaFeO3 ceramics. The studied sample was prepared by a citrate gel method. Structural and microstructural properties are analyzed from the XRD pattern and SEM micrograph. The anomalies in the dielectric constant versus temperature plots are analyzed on the basis of polarization induced by the Maxwell-Wagner mechanisms and ferromagnetic interaction between the Fe3+ ions driven by the oxygen vacancy mediated Fe3+–Vo –Fe3+ exchange interaction A giant dielectric permittivity in the order of ∼105 was observed in the sample even at the room temperature for 100 Hz. The colossal dielectric constant in LaFeO3 is mainly driven by the internal barrier layer capacitor (IBLC) formation. The formation of IBLC was explained on the basis of highly insulating grain boundary and less resistive/semiconducting grain, which was confirmed from both the resistance and capacitance of grain and grain boundary from the impedance analysis. The non-Debye-type relaxation process associated with the grain and grain boundary effect was investigated from the broad and asymmetric relaxation peak. The relaxation time for both the grain and grain boundary effect was also calculated. In addition to this, we have also analyzed the normalized bode plot of imaginary part of impedance and electrical modulus which suggests the relaxation process dominated by the short-range movement of charge carriers.The present investigations mainly focused on the colossal dielectric response and complex impedance analysis of LaFeO3 ceramics. The studied sample was prepared by a citrate gel method. Structural and microstructural properties are analyzed from the XRD pattern and SEM micrograph. The anomalies in the dielectric constant versus temperature plots are analyzed on the basis of polarization induced by the Maxwell-Wagner mechanisms and ferromagnetic interaction between the Fe3+ ions driven by the oxygen vacancy mediated Fe3+–Vo –Fe3+ exchange interaction A giant dielectric permittivity in the order of ∼105 was observed in the sample even at the room temperature for 100 Hz. The colossal dielectric constant in LaFeO3 is mainly driven by the internal barrier layer capacitor (IBLC) formation. The formation of IBLC was explained on the basis of highly insulating grain boundary and less resistive/semiconducting grain, which was confirmed from both the resistance and capacitance of grain and grain boundary from the impedance analysis. The non-Debye-type relaxation process associated with the grain and grain boundary effect was investigated from the broad and asymmetric relaxation peak. The relaxation time for both the grain and grain boundary effect was also calculated. In addition to this, we have also analyzed the normalized bode plot of imaginary part of impedance and electrical modulus which suggests the relaxation process dominated by the short-range movement of charge carriers.