KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Author: search.filters.author.Udeye, ThanyaSubject: search.filters.subject.ferroelectric properties

Search Results

Now showing 1 - 2 of 2
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Phase Evolution, Microstructure and Electrical Behavior of (Ba0.97Ca0.03)(Ti0.94-x/2Sn0.06-x/2Wx)O3 Ceramics Synthesized via the Solid-State Combustion Technique
    (2022-01-01)
    Udeye, Thanya
    ;
    Onsri, Thanakrit
    ;
    Yotthuan, Surirat
    ;
    Pulphol, Phieraya
    ;
    Vittayakorn, Naratip
    This research studied the effect of W<sup>4+</sup> substitution on the phase formation, microstructure and electrical properties of (Ba<inf>0.97</inf>Ca<inf>0.03</inf>)(Ti<inf>0.94-x/2</inf>Sn<inf>0.06-x/2</inf>W<inf>x</inf>)O<inf>3</inf> (BCTSW) ceramics with x = 0, 0.005, 0.010, 0.015 and 0.020 mol%. The BCTSW ceramics were synthesized by the solid-state combustion technique, using glycine as fuel. The powders and green pellets of BCTWS were calcined and sintered at 1100 °C for 4 h and 1400 °C for 2 h, respectively. A pure perovskite phase with coexisting orthorhombic and tetragonal phases were observed for all samples. The content of the tetragonal phase increased when x rose, as verified by the Rietveld refinement procedure. The average grain size and the measured density of the samples tended to decrease from 35 ± 0.56 to 1.9 ± 0.12 µm and 5.59 to 4.88 g/cm<sup>3</sup>, respectively, when x increased. The dielectric behavior of the ceramics strongly degenerated upon W<sup>4+</sup> substitution. The undoped BCTS ceramic showed a well-saturated P-E hysteresis loop. With W<sup>4+</sup> substitution, the samples’ P-E loops became unsaturated and a leakage current was created.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Phase evolution, microstructure and electrical response of KNNT ceramics with Li+ substitution and doping
    (2022-01-01)
    Yotthuan, Surirat
    ;
    Udeye, Thanya
    ;
    Prasertpalichat, Sasiphon
    ;
    Pulphol, Phieraya
    ;
    Vittayakorn, Naratip
    Lead-free (K<inf>0.5</inf>Na<inf>0.5</inf>)(Nb<inf>0.7</inf>Ta<inf>0.3</inf>)O<inf>3</inf> (KNNT) ceramics with Li<sup>+</sup> substitution (KN<inf>0.5-x</inf>Li<inf>x</inf>NT) and direct (KNNT-xLi) doping at x = 0, 0.01, 0.02, 0.03 and 0.04 mol% were synthesized by the solid-state combustion route. The phase, microstructure, dielectric and ferroelectric properties of the ceramics were examined. The XRD pattern of the ceramics revealed orthorhombic and tetragonal phases in all specimens. The Rietveld refinement procedure showed that increasing either the Li<sup>+</sup> substitution or doping levels enhanced the amount of the tetragonal phase. It was found that Li<sup>+</sup> doping, either substitutional or additional, enhanced the Curie temperature (T <inf>C</inf>) by increasing the tetragonal distortion, while the dielectric constant (ε <inf>C</inf>) decreased. The good remanent P-E loops of the KN<inf>0.5-x</inf>Li<inf>x</inf>NT ceramics were found with x = 0.01 (P <inf>r</inf>∼10.89 µC/cm<sup>2</sup> and E <inf>C</inf>∼13.09 kV/cm), while for KNNT-xLi ceramics, it was obtained with x = 0.02 (P <inf>r</inf>∼15.65 µC/cm<sup>2</sup> and E <inf>C</inf>∼11.46 kV/cm), which were confirmed by remanent P-E hysteresis measurements.