A5079492803- Microwave Dielectric Ceramics Synthesis
- Ferroelectric and Piezoelectric Materials
- Multiferroics and related materials
- Acoustic Wave Resonator Technologies
- Electronic and Structural Properties of Oxides
- Optical and Acousto-Optic Technologies
- Advanced Thermoelectric Materials and Devices
- Dielectric properties of ceramics
- Engineering Applied Research
Uniwersytet Komisji Edukacji Narodowej w Krakowie
2019-2023
Pedagogical University
2019
Abstract Lead-free Na 0.5 Bi TiO 3 (NBT) ceramics were prepared via a conventional oxide-mixed sintering route and their electrical transport properties investigated. Direct current (DC, σ DC ) alternating (AC, AC conductivity values, polarization (first measurements) depolarization current, current–voltage ( I – U characteristics measurements), the Seebeck coefficient (α) determined under various conditions. The mechanism of phenomena observed for investigated samples found to be typical....
The single crystals of lead-free Na0.5Bi0.5TiO3 were grown using the Czochralski method. energy gaps determined from X-ray photoelectron spectroscopy (XPS) and optical measurements approximately 2.92 eV. current-voltage characteristics, depolarization current, dc (σdc) ac (σac) electrical conductivity, Seebeck coefficient investigated. frequency/temperature-dependent properties also measured analyzed through complex impedance spectroscopy. An overlapping reversible insulator-metal transition...
Lead-free Ba1−xSrxTiO3 (BST) (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.45) ceramics were successfully prepared via the solid-state reaction route. A pure perovskite crystalline structure was identified for all compositions by X-ray diffraction analysis. The basic phase transition temperatures in these studied over a wide temperature range. change symmetry from tetragonal to cubic detected, which further proven phonon anomalies composition/temperature-dependent Raman spectra. incorporation of Sr2+...
Na0.5Bi0.5TiO3 (NBT) and Fe- Mn-modified NBT (0.5 1 mol%) ceramics were synthesized by the solid-state reaction method. The crystal structure, dielectric thermal properties of these measured in both unpoled poled states. Neither addition iron/manganese to nor poling changed average structure material; however, changes observed short-range scale. shapes Bragg peaks their 2Θ-position Raman spectra indicated a temperature-driven structural evolution similar that pure NBT. It was found...
The Fe-substituted Na0.5Bi0.5TiO3 (NBT) ceramics were prepared through solid-state reaction technique. X-ray diffraction analysis indicated the formation of perovskite structure with rhombohedral symmetry. It was found that 0.5 mol% Fe and 0.1 dopant concentration increases depolarization temperature Td, Tm, dielectric loss electric conductivity. effects can be mainly result free charges (FeTi′-VO∙∙)∙ microdipoles appearance due to Fe-introduced NBT. shown a prior field poling process...
High-quality and large-size single crystals of lead-free Na0.5Bi0.5TiO3 were grown using the Czo-chralski technique. The had pure perovskite structure with rhombohedral symmetry translucent in visible near infrared spectral ranges recorded interval 350-1050 nm. energy gaps determined from X-ray photoelectron spectroscopy (XPS) optical measurements approximately 2.92 eV. current-voltage characteristics, depolarization current, dc (σdc) ac (σac) electrical conductivity,...
The mechanical properties of Mn- and Fe-doped Na
Low-levels of Nb-doped (≤2 at.%) NBT ceramics were synthesized using a conventional ceramic technique. The XRD analysis indicated the formation perovskite structure with rhombohedral symmetry where Nb-doping tends to expand lattice. dielectric characteristics and piezoelectric coupling are enhanced as result microdefect dipole ferroelectric order disturbance. It was shown that E-poling influences properties under investigation. This includes decrease electric permittivity (ϵ) an increase...
The behavior of Ba1-xSrxTiO3 ceramics (x = 0, 0.3, 0.4 and 0.45) in both unpoled poled states was studied using XRD, SEM, DSC dielectric methods. exhibit pure perovskite structure with tetragonal symmetry for x 0.3 pseudocubic 0.45. It found that the substitution SrTiO3 to BaTiO3 significantly influences properties under investigation, leading a shift phase transitions weakness ferroelectric properties. This suggests effects are mainly due differences ionic size between dopant host ions more...
The Mn-substituted NBT ceramics were prepared by the conventional ceramic fabrication technique. X-ray diffraction (XRD) studies indicated formation of perovskite phase with rhombohedral symmetry and small amount second phase. It was found that 0.5mol% 0.1mol% dopant concentration enhances piezoelectric coefficients d33 k33, increases depolarization temperature Td decreases dielectric loss. Dielectric study showed existence a diffuse transition at Tm ≈ 320°C. shown prior electric field...
Ba1-xSrxTiO3 (BST) (x = 0, 0.1 and 0.2) ceramics were prepared by the solid-state reaction method their structural, thermal dielectric behavior was studied. The increasing concentration of Sr2+ ions leads to shift Tc toward lower temperature. results obtained are discussed in terms microstructural/structural effects incorporation into BaTiO3. It is shown that E-poling influences properties under investigation. This includes modification local structure, response temperature phase...
The paper presents the results of measurements a solid solution (1-x)K<sub>0.5</sub>Bi<sub>0.5</sub>TiO<sub>3</sub>-xSrTiO<sub>3</sub> (<i>KBT-ST</i>) ceramics with (for) x=0.001 for two different sintering temperatures (cases times sintering): (1) at temperature 1303K 6 hours (<i>KBT-ST</i> 1) and (2) 1313K 2). In both cases, X-ray diffraction study demonstrated perovskite structure small amount second phase. Microstructure research SEM allowed to observe well-developed grains obtained...
IN THE (1-x)PbTiO 3 -x(Na 0.5 Bi )TiO CRYSTALS Crystals of PbTiO and 0.9PbTiO -0.1(Na0.5 were obtained by the flux growth method whereas crystals (Na ) TiO Czochralski method.Raman spectroscopy polarized light microscopy performed at room temperature.The Raman spectra shown significant changes comparing to base materials .A domain structure was investigated use microscopy.Dielectric permittivity measurements carried out in temperature range from 20°C 550°C a frequency 1 kHz MHz.These showed...
Most studies of ferroelectric materials were focused on polycrystalline ceramics. However, it is difficult to improve their properties significantly (particularly piezoelectric one) due grain/grain boundaries, compositional homogeneity, isotropic characteristics, and structural defects. It commonly accepted that single crystals often have better behavior less defects than In this paper, we provide the processing technology lead-free Na0.5Bi0.5TiO3 Na0.5Bi0.5TiO 3-based crystals....