A5052948879- Ferroelectric and Piezoelectric Materials
- Multiferroics and related materials
- Acoustic Wave Resonator Technologies
- Microwave Dielectric Ceramics Synthesis
- Dielectric properties of ceramics
- Electronic and Structural Properties of Oxides
- Magnetic and transport properties of perovskites and related materials
- ZnO doping and properties
- Solid-state spectroscopy and crystallography
- Gas Sensing Nanomaterials and Sensors
- Dielectric materials and actuators
- Glass properties and applications
- Ferroelectric and Negative Capacitance Devices
- Ga2O3 and related materials
- Copper-based nanomaterials and applications
- Optical and Acousto-Optic Technologies
- Photorefractive and Nonlinear Optics
- Advanced Memory and Neural Computing
- Semiconductor materials and devices
- Chalcogenide Semiconductor Thin Films
- Electrical and Thermal Properties of Materials
- Liquid Crystal Research Advancements
- Theoretical and Computational Physics
- Advanced Sensor and Energy Harvesting Materials
- Material Dynamics and Properties
Changwon National University
2014-2024
Government of the Republic of Korea
2015
Seoul National University
1993-2002
Korea Institute of Ceramic Engineering and Technology
1996-1998
Korea Institute of Science and Technology
1996-1998
Korean Association Of Science and Technology Studies
1996-1997
A bismuth ferrite and barium titanate solid solution compound can achieve good piezoelectric properties with a high Curie temperature when fabricated low-temperature sintering followed by water-quenching process, no complicated grain alignment processes performed. By adding the super-tetragonal gallium oxide to compound, are as those of lead zirconate ceramics.
Time-dependent polarization relaxation behavior induced by a depolarization field ${E}_{d}$ was investigated on high-quality ultrathin ${\mathrm{SrRuO}}_{3}/{\mathrm{BaTiO}}_{3}/{\mathrm{SrRuO}}_{3}$ capacitors. The values were determined experimentally from an applied external to stop the net relaxation. These agree with those electrostatic calculations, demonstrating that large inside ferroelectric layer could cause severe For numerous devices of capacitor configuration, this effect will...
We investigated domain kinetics by measuring the polarization switching behaviors of (111)-preferred polycrystalline $\mathrm{Pb}(\mathrm{Zr},\mathrm{Ti}){\mathrm{O}}_{3}$ films, which are widely used in ferroelectric memories. Their at various electric fields and temperatures could be explained assuming Lorentzian distribution logarithmic domain-switching times. suggested that local field variation due to dipole defects pinning sites explain distribution.
Flexoelectricity can play an important role in the reversal of self-polarization direction epitaxial BiFeO3 thin films. The flexoelectric and interfacial effects compete with each other to determine state. In Region I, is downward because effect more dominant than effect. II, upward, becomes
The polarization switching kinetics of epitaxial Pb(Zr0.4Ti0.6)O3 thin films were investigated by measuring write pulse-width dependences switched ΔP(t) under various applied electric fields. It was found that follows the predictions Kolmogorov–Avrami–Ishibashi model quite well. However, detailed behaviors different for low and high field regions, which separated out around 220kV∕cm. coercive also showed frequency depending on region. These differences attributed to changes in kinetics. A...
Structure property relations in (1−x)(Bi0.5Na0.5)TiO3-xBaTiO3 ceramics were investigated at x=0–10 mol %. A solid solution with either rhombohedral or tetragonal symmetry was confirmed a morphotropic phase boundary (MPB) x=5–7 Grains became small increasing x possibly due to grain pinning by BaBi′–BaNa•. Lattice distortion key factor affecting piezoelectric coefficient (d33) and depolarization temperature (Td). Both 90−α cT/aT lattice smaller toward the MPB causing poling field depoling...
We investigated the pinning dominated domain-wall dynamics under an ac field by studying frequency $(f)$ dependence of hysteresis loops a uniaxial ferroelectric (FE) system. measured fully saturated polarization-electric $(P\text{\ensuremath{-}}E)$ high-quality epitaxial 100-nm-thick ${\text{PbZr}}_{0.2}{\text{Ti}}_{0.8}{\text{O}}_{3}$ capacitors at various $f$ (5--2000 Hz) and temperatures $T$ (10--300 K). observed that coercive ${E}_{C}$ is proportional to ${f}^{\ensuremath{\beta}}$ with...
A phase diagram of A- and B-site co-substituted lead-free incipient piezoceramics is schematically constructed on the basis crystal structure electromechanical, dielectric piezoelectric properties.
A long standing problem of domain switching process - how domains nucleate is examined in ultrathin ferroelectric films. We demonstrate that the large depolarization fields films could significantly lower nucleation energy barrier (U*) to a level comparable thermal (kBT), resulting power-law like polarization decay behaviors. The "Landauer's paradox": U* thermally insurmountable not critical issue empirically find universal relation between behavior and U*/kBT.
Three different series of lead-free ceramics, i.e., (1-y)Bi1.03(1-x)LaxFeO3–yBaTiO3 (y = 0.27, x 0.00–0.12), 0.30, 0.00–0.10), and 0.33, 0.00–0.08) are prepared via a conventional solid-state reaction with water quenching. From X-ray diffraction electrical property measurements, two morphotropic phase boundaries (MPBs) discovered in all three ceramic systems. The first MPB (MPB-I) appeared between rhombohedral tetragonal phases, whereas the second (MPB-II) cubic-like phases. highest direct...