•Mo doped KTP 24 × 18 × 8 mm3 single crystal grown by self flux method.•Powder X-ray diffraction data confirms the structural stability of pure and doped crystals.•The Mo: KTP single crystal shows ...low ionic conductivity and polarization with a low coercive field.
Pure and molybdenum-doped potassium titanyl phosphate (KTP) single crystals were grown using the spontaneous crystallization by self-flux (K6P4O13) method, and their structural, optical, and electrical properties were studied. The structural properties were confirmed using powder XRD analysis, and there is no significant change in the basic crystal structure observed for the Mo doped KTP single crystal. The grown crystals' optical properties were analyzed using the ultraviolet-transmission spectral analysis, and the bandgap energy was calculated. The dielectric constant, dielectric loss, and electrical conductivity of the crystals were measured at different frequencies and temperatures and are discussed. P-E hysteresis loop response of Mo: KTP at different applied electric fields and temperature shows a low coercivity response. The ferroelectric fatigue analysis shows better homogeneity of the material.
The present study elucidated that the influence of various lanthanide ions (Ho, Ce, Nd, and Eu) doped in Bi
0.5
(Na
0.80
K
0.20
)
0.5
TiO
3
–SrZrO
3
(BNKT–SZ) ceramics was synthesized by conventional ...solid-state reaction technique. Their phase structure, piezoelectric, ferroelectric, dielectric, thermal stability, and energy-storage properties were investigated. The powder X-ray diffraction analysis of ceramics revealed the formation of pure perovskite structure along with the pseudo-cubic phase structure. The microstructural investigation showed variation in grain size due to lanthanide doping. The elemental distribution of the chemical composites of lanthanide-doped ceramic sample was identified by EDX analysis. The remnant polarization (P
r
) and maximum polarization (P
max
) values for BNKT–SZ ceramic showed the values of 6.78 μC/cm
2
and 8.68 μC/cm
2
, respectively, under the electric field of 90 kV/cm. Eu
3+
-doped BNKT–SZ ceramics showed a better energy-storage performance, (W
rec
) ~ 0.75 J/cm
3
and good temperature stability. Dielectric permittivity of the ceramics was studied as a function of temperature ranging from room temperature to 500 °C in the frequency ranges from 1 to 100 kHz. The piezoelectric coefficient (d
33
) measured on the poled compositions exhibited a maximum value of 127 pC/N for Ce
3+
. For all compositions, the temperature-dependent piezoelectric coefficient was found to be stable up to the transition temperature. The results indicate that the lanthanide-doped BNKT–SZ ceramics are promising candidates for energy-storage capacitor and piezoelectric applications.
The ferroelectric and piezoelectric properties of Sr2Nb2O7–La2Ti2O7 (SNB-LT) solid solution ceramics have been studied. The La and Ti ions were substituted into the Sr2Nb2O7 (SNB) lattice and their ...resultant phase of SNB-LT has lattice distortion. The Rietveld refinement parameters from the XRD patterns corroborate a solid solution of Sr2Nb2O7–La2Ti2O7. The addition of La3+ and Ti4+ dampens the SNB intra-structural phase. Raman spectroscopy confirmed the internal lattice relaxation due to the Ti(Nb)O6 octahedron in the lattice. At 2×106 Hz, the dielectric permittivity of SNB-LT-1, SNB-LT-2, and SNB-LT-3 is 17.2, 17.5, and 21.3, respectively, with σac conductivity in the order of 10−5 S/m. With an increase in Ti(Nb)O6 distortion, the piezoelectric coefficient of SNB-LT-1, SNB-LT-2, and SNB-LT-3 increases linearly as 6.3, 8.1, and 9.3 pC/N. The temperature-dependent ferroelectric polarization of SNB-LT-1, SNB-LT-2, and SNB-LT-3 has been tested, and a substantial rise in polarization has been demonstrated up to 120 °C. At 120 °C, the SNBLT solid solution showed a two-fold increase in remnant polarization.
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•Layer perovskites ceramics of Sr2Nb2O7–La2Ti2O7 solid solution prepared with high TC.•Outstanding d33 of ∼0.91 pC/N as well as low σac of 10−5 S/cm at 5 MHz.•Realized good ferroelectricity at 120 °C.
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•The PZT:RE3+ ceramic was prepared via solid state reaction method.•RE3+-doped ceramic exhibits high dispersions in dielectric permittivity.•Rare earth metals in PZT solid solution ...reduces the phase transition up to 30 °C.
PbZr0.52Ti0.48O3 with simultaneous addition of (RE3+:La3+, Nd3+, Dy3+) synthesized by conventional solid state reaction technique. The effect of La, Nd and Dy addition on structural, electrical and optical properties of PZT ceramic are investigated. Powder X-ray diffraction pattern shows that the pure perovskite structure and rare earth element completely diffused into the PZT lattice during sintering. Scanning electron microscope observation indicates that a small amount of La3+, Nd3+, Dy3+ ions does not affect the microstructure. Temperature and frequency dependent dielectric properties of rare earth doped PZT ceramic are investigated. The local micro structural heterogeneity has been induced to PbZr0.52Ti0.48O3: (RE3+: La3+, Nd3+, Dy3+) which is studied by Raman spectroscopy. The rare earth doped PbZr0.52Ti0.48O3 ceramics have sensitive phase transition behavior from 275 to 310 °C. The impedance spectroscopic studies show that oxygen vacancies role in ionic conduction of rare earth ions doped PbZr0.52Ti0.48O3 ceramics for different temperature. The PbZr0.52Ti0.48O3:Nd3+ composition has formidable structural and electrical properties of low conductivity (~10–3 S/m) and low transition temperature (275 °C). At room temperature, this composition exhibits a high piezoelectric coefficient of (d33 = 149pC/N). The PbZr0.52Ti0.48O3:RE3+ ceramics exhibits good thermal stability up to 400 °C that assure for high temperature piezoelectric applications.
Rare-earth-doped alkali halide single crystals KCl:Eu, KCl:Ce, and KCl:Eu,Ce were grown from melt using the Czochralski technique, and optical characterization was carried out with the prime focus on ...dosimetric applications. The grown crystals were investigated using XRD analysis, PL analysis, TSL measurements, and OSL measurements. The XRD of the crystals matched well with ICDD patterns (00-041-1476), and diffraction peaks can be assigned to the KCl structure, indicating that all the crystals have the same structure as KCl. The enhanced intensity of TSL and OSL was observed for co-doping of (Eu, Ce) in KCl crystals as compared to single doping. The appearance of a single glow peak in KCl:Eu,Ce at 230°C compared to single-doped KCl:Ce crystals suggested the use of the material in TL dosimetry. The intensity of OSL also showed a two-fold increase compared to single-doped crystals, suggesting its use in OSL dosimetry. PL studies showed a very high enhancement of intensity in Eu
2+
emissions, reaching a maximum of about 421 nm in the (Eu
2+
, Ce
3+
) co-doped crystal compared to single-doped crystals. This justifies the occurrence of energy transfer from Ce
3+
to Eu
2+
in the KCl host lattice. These results showed that KCl:Eu,Ce acts as a potential TL and OSL dosimeter due to its high sensitivity to ionizing radiation.
•An organic diphenylmethanol single crystal was grown by vertical Bridgman technique.•The band gap value of the grown crystal is estimated as 4.43 eV.•The third order NLO parameters n2, β and χ3 ...values were evaluated by Z-scan studies.•The laser damage threshold of the crystal is found to be 15.2 GW/cm2.
An organic nonlinear optical diphenylmethanol single crystal was grown by vertical Bridgman technique using single wall ampoule. The lattice parameters and crystal system of grown crystal were confirmed by single crystal XRD analysis. The functional groups present in the crystal were identified by FTIR analysis. The thermal properties of the grown crystal were studied by thermo-gravimetric and differential thermal analyses. UV–vis-NIR spectroscopic analysis shows that the crystal has low cut-off wavelength at 271 nm and band gap value of 4.43 eV. The fluorescence spectrum indicates that the crystal exhibits emission at 289 nm wavelength in UV region. The second harmonic generation efficiency of diphenylmethanol was determined by Kurtz and Perry powder technique. The third order nonlinear optical parameters like nonlinear refractive index (n2), nonlinear absorption coefficient (β) and third order nonlinear susceptibility (χ3) of the crystal were determined by Z-scan technique using cw Nd:YAG laser light of wavelength 532 nm. The self-defocusing and saturation absorption nature of the crystal were identified from Z-scan closed and open aperture methods respectively. The crystal exhibits good power limiting behaviour due to non linear refraction. The laser damage threshold study indicates that the crystal has no surface damage upto 29.5 mJ.
White light emitting SrLa2−xO4:Dy3+/0.05 Ca2+phosphors are prepared by solid state reaction technique at 1200◦C.X-ray diffraction method interprets the phase structure of the material while the ...luminescence properties of the co-doped SrLa2O4 phosphors and energy transfer mechanism are scrutinized by photoluminescence spectra analysis. Two main emission peaks are attributed at 484 nm and 571 nm due to the Dy3+ions under 324 nm excitation wavelength. The resultant output is in consonance with the synthesis white-light emitting phosphors can be obtained from the single host material at x = 0.06 doping concentration Dy3+ ions. The phosphors reveal a strong absorption band obtained in UV region and the observed white-light emission with chromaticity co-ordinates read x = 0.326, y = 0.362. The inference illustrates the synthesis material prospective candidate for white LED applications.
•Synthesis of SrLa2-xO4:xDy3+/0.05Ca2+ by solid state reaction method in single step synthesis process.•The La3+ replaced by Ca2+ ions to generate the oxygen vacancies which obey the Kroger-Vink defects•Eco friendly nature and its makes from oxide materials which have high thermal stability characteristics.
•Holmium doped rubidium titanyl phosphate single crystal was grown by high temperature flux method using self flux composites.•The Ho: RTP single crystal shows lower value of coercive field and good ...temperature and frequency stability.•Ho: RTP single crystal exhibits good optical transmittance up to 84% in the entire visible region.
The holmium doped rubidium titanyl phosphate single crystal was grown using a high-temperature flux method using rubidium polyphosphate as a flux compound. The structural nature of the grown Ho: RTP single crystal has been confirmed by powder XRD analysis. The addition of Ho dopant shows variations in the diffraction peaks refer to the combination of holmium with the RTP lattice. The UV absorption and transmittance study show no visible absorption induced by holmium. The electrical parameters like, dielectric constant, dielectric loss, AC conductivity and impedance have been studied up to the Curie point level of the material, and the results indicating that the doping of holmium reduces the electrical activities in the RTP single crystal, and there is no change in the Curie point of the Ho: RTP single crystal compared to pure RTP. The ferroelectric result shows that the polarization and coercive field of material have a lower value than the pure RTP single crystal due to the presence of holmium in the RTP, which is very useful for periodically poled device applications. Ferroelectric fatigue test on Ho: RTP shows that the grown crystal does not undergo polarization decay up to 5000 frequency cycles.
•Internal friction and shear modulus data are presented for a 7 orders of magnitude frequency range.•A law describing the imaginary compliance component in this range is determined.•A new method for ...the determination of the Gibbs activation energy of relaxation is suggested.•It is argued that relaxation origin is related to the interstitial-type defects inherited from the melt.•It is assumed that at least defect-related three mechanisms of energy losses are operating.
Neodymium doped Rubidium Titanyl Phosphate (RTP) single crystal was grown using a high-temperature flux solution method with rubidium polyphosphate flux. Though doping does not induce changes in growth temperature, variations in material properties were observed while characterizing the grown crystal. Powder x-ray diffraction and high resolution x-ray diffraction analysis of Nd: RTP single crystal suggested the orthorhombic structure with small structural distortion and good crystalline nature. The presence of neodymium and other elements in the crystal was confirmed using EDAX analysis. The optical quality of the material was studied using optical transmittance and absorption studies. The variation in the optical band gap due to Nd doping was also analyzed. The dielectric polarization, ion hopping, activation processes, dielectric, electrical conductivity, and resistivity nature of the grown crystal were studied using impedance analysis. The properties were studied from room temperature to 850 °C, in the frequencies range from 100 Hz to 8 MHz. Then the results were compared with flux-grown pure RTP single crystals. The result exhibited superior properties on Nd doping in RTP. The low and static dielectric constant exhibited by Nd: RTP made it suitable for NLO applications. The ferroelectric nature of the Nd: RTP was analyzed from room temperature to 180 °C at an applied field of 4 kV and the PE loop was found with values of polarization and coercive field as 0.15 μC/cm2 and 1.79 kV/cm, respectively. Nd: RTP does not show any polarization decay up to 5000 frequency cycles confirmed by fatigue analysis.
This work elevates the relevance of kinetic parameters of nucleation and thermal decomposition for water soluble crystals. The positive soluble Potassium Dihydrogen Phosphate (KDP) and negative ...soluble Lithium Sulfate Monohydrate (LSMH) materials were chosen for the kinetic evaluation. The results obtained from the classical nucleation theory are verified with the kinetic parameters which are evaluated from thermo gravimetric analysis. Nucleation parameters of a crystallization process such as interfacial energy (σ), volume free energy (ΔGv), critical energy barrier for nucleation (ΔG⁎), radius of the critical nucleus (r⁎) and nucleation rate (J) of the positive (KDP) and negative solubility (LSMH) crystals are determined from the classical nucleation theory of solubility–enthalpy relation. The kinetic parameters viz. the order of reaction, enthalpy, Gibbs free energy of activation, frequency factor, and entropy of activation are obtained from the TG based models viz. Horowitz–Metzger, Coats–Redfern and Piloyan–Novikova. The effect of varying temperature with relative variation on Gibbs free energy for both positive and negative solubility crystals is also discussed. The developed model holds good for both positive and negative solubility crystals.
•Nucleation parameters for positive soluble KDP crystals and negative soluble LSMH crystals are evaluated.•Calculated results are verified by thermo gravimetric analysis.•Applications of thermo gravimetric based models namely Horowitz–Metzger, Coats–Red fern and Piloyan–Novikova were reported.•The effect of varying temperature with relative variation on Gibbs free energy for both positive and negative solubility crystals is also discussed.
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