A5042028074- Ferroelectric and Piezoelectric Materials
- Multiferroics and related materials
- Microwave Dielectric Ceramics Synthesis
- Acoustic Wave Resonator Technologies
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Electronic and Structural Properties of Oxides
- Solid-state spectroscopy and crystallography
- Magnetic and transport properties of perovskites and related materials
- Photorefractive and Nonlinear Optics
- Dielectric properties of ceramics
- Nuclear Physics and Applications
- Bone Tissue Engineering Materials
- Glass properties and applications
- Dielectric materials and actuators
- Advancements in Battery Materials
- Advanced Battery Materials and Technologies
- Solidification and crystal growth phenomena
- Nuclear materials and radiation effects
- Advancements in Solid Oxide Fuel Cells
- Advanced Sensor and Energy Harvesting Materials
- Material Properties and Applications
- Extraction and Separation Processes
- High-pressure geophysics and materials
- Advanced ceramic materials synthesis
Karlsruhe Institute of Technology
2015-2024
Fraunhofer Institute for Mechanics of Materials
2023-2024
Technical University of Darmstadt
2005-2021
Deutsches Elektronen-Synchrotron DESY
2015-2021
Robert Bosch (Germany)
2020-2021
Frankfurt University of Applied Sciences
2021
Goethe University Frankfurt
2021
Tallinn University of Technology
2021
UNSW Sydney
2014-2020
Materials Science & Engineering
2014-2020
High energy density was achieved in lead-free La-doped AgNbO<sub>3</sub> antiferroelectric ceramics.
Here, we introduce phase change mechanisms in lead-free piezoceramics as a strategy to utilize attendant volume for harvesting large electrostrain. In the newly developed (K,Na)NbO3 solid-solution at polymorphic boundary combine atomic mapping of local polar vector with situ synchrotron X-ray diffraction and density functional theory uncover interpret its underlying nature. We demonstrate that an electric field-induced transition between orthorhombic tetragonal phases triggers dramatic...
ABO
The origin of the electric field-induced strain in polycrystalline ceramic 0.92Bi 1/2 Na TiO 3 –0.06BaTiO –0.02K NbO was investigated using situ high-resolution X-ray and neutron diffraction techniques. initially existing tetragonal phase with pseudocubic lattice undergoes a reversible transition to significantly distorted rhombohedral under field, accompanied by change oxygen octahedral tilting from 0 c + − angle. polarization values for phases were calculated based on structural...
An in situ structural description of the origin ferroelectric properties as a function applied electric field E was obtained by synchrotron x-ray diffraction. A setup used to average effects preferred orientation induced strong piezoelectric strain and solve crystal structure field. Hence, we were able describe microscopic macroscopic ferro- most widely material, lead zirconate titanate.
The structural behavior of ceramic solid solutions (1\ensuremath{-}$x$)Na${}_{1/2}$Bi${}_{1/2}$TiO${}_{3}$--$x$K${}_{1/2}$Bi${}_{1/2}$TiO${}_{3}$ (NBT-KBT) was studied using high-resolution powder diffraction and transmission electron microscopy. A temperature-independent morphotropic phase boundary (MPB) separating NBT-like pseudorhombohedral (R) KBT-like pseudotetragonal (T) phases observed at $x$ \ensuremath{\approx} 0.2. For $x<0.2$, both local average room-temperature structures are...
Due to growing concern for the environment and human health, searching high-performance lead-free piezoceramics has been a hot topic of scientific industrial research. Despite significant progress achieved toward enhancing piezoelectricity, further efforts should be devoted synergistic improvement piezoelectricity its thermal stability. This study provides new insight into these topics. A KNN-based ceramic material is presented, which features large piezoelectric coefficient (d33) exceeding...
The effect of external mechanical fields on relaxor $0.94(\mathrm{N}{\mathrm{a}}_{1/2}\mathrm{B}{\mathrm{i}}_{1/2})\mathrm{Ti}{\mathrm{O}}_{3}\text{\ensuremath{-}}0.06\mathrm{BaTi}{\mathrm{O}}_{3}$ was investigated by means temperature- and stress-dependent dielectric constant measurements between 223 673 K. Analogous to previous investigations that showed an electric-field-induced ferroelectric long-range order in ferroelectrics, we show compressive stress can also result the transition...
Material extrusion (MEX) of thermoplastic filaments represents one the most widely adopted additive manufacturing (AM) technologies. Unlike vat photopolymerization and powder-bed fusion methods that require high energy sources such as UV light lasers, this fabrication method can be adapted for ceramics by using ceramic loaded feedstock, yet still employing relatively cheap equipment meant polymeric materials with little adaptation process parameters; potentially enables a broader diffusion...
High-performance dielectric energy-storage ceramics are beneficial for electrostatic capacitors used in various electronic systems. However, the trade-off between reversible polarizability and breakdown strength poses a significant challenge simultaneously achieving high energy density efficiency. Here strategy is presented to address this issue by constructing dual-phase structure through situ phase separation. (Bi
Local structure information of relaxor ferroelectrics is key to a clear understanding their structure–property relationships. The size polar nanoregions determined based on the local atomic displacement and dielectric response.
The phase diagram of the lead-free piezoelectric (1 − x )K 0.5 Na NbO 3 – Bi 1/2 TiO system has been studied by high-resolution synchrotron powder diffraction, neutron diffraction and selected area electron diffraction. two materials K form an infinite substitution solid solution. orthorhombic ( O ), monoclinic M tetragonal T ) rhombohedral R phases coexistence Pm + P 4 mm for 0.02 < ≤ 0.14, bm pseudocubic (Pm{\overline 3}m) 0.14 0.87 c 0.96 have investigated at room temperature, with a...
The poling behavior of a lead-zirconate-titanate piezoelectric ceramic is investigated by measurements the ferroelectric hysteresis, longitudinal coefficient, and field-cooling experiments. At high temperatures, decrease in coercive field facilitates at lower electric fields, resulting higher values coefficient. However, there exists threshold about 150 V/mm, below which fully poled samples cannot be obtained even when cooling from temperatures above transition. Further, temperature regime...
The correspondence between the temperature dependence of phase structures and experimental physical properties was made clear for first time in Bi1/2Na1/2TiO3 system according to situ XRD, Raman impedance spectroscopy. XRD profiles show pseudo-cubic symmetry independent temperature, while one models disappears near 620 K, indicating that local increases. main relaxation electric modulus spectra can be divided into four regions, characterizing thermal evolution polar nanoregions (PNRs) with...
In-situ synchrotron XRD measurements of the magnetocaloric material LaFe11.8Si1.2 are used to understand virgin effects and asymmetry underlying first order magnetovolume transition. A remarkable change transition kinetics occurs after cycle, which we attribute formation cracks originating from volume change. Tomographic imaging revealed that bulk disintegrates via an interlocked state where fragments loosely connected. Though have opened between fragments, is sharp, magnetostatic...
In this study, the evolution of field induced mechanisms in lead-free piezoelectric ceramics (1−x)Bi1/2Na1/2TiO3-xBaTiO3 with x = 0.06 and 0.07 was investigated by transmission electron microscopy, neutron, X-ray diffraction. Preliminary investigations revealed a strong degradation macroscopic electromechanical properties within first 100 bipolar electric cycles. Therefore, structural investigation focuses on comparative diffraction study freshly prepared, poled, fatigued specimens....
A brief review of in situ powder diffraction methods for battery materials is given. Furthermore, it demonstrated that the new beamline P02.1 at synchrotron source PETRA III (DESY, Hamburg), equipped with a electrochemical test cell design and fast two-dimensional area detector, enables outstanding conditions studies on complex crystal structures. For instance, time necessary to measure pattern can be reduced region milliseconds accompanied by an excellent quality. It shown even medium...
The nature of the cubic-like state in lead-free piezoelectric ceramics 0.5K0.5Na0.5NbO3-0.5Na0.5Bi0.5TiO3 (KNN-50BNT) has been examined detail by synchrotron x-ray diffraction (SD), selected area electron (SAED), neutron (ND), and temperature dependent dielectric characterization. SD pattern KNN-50BNT presents a pure perovskite structure with pseudocubic symmetry. However, superlattice reflections were observed SAED completely indexed tetragonal symmetry P4bm space group ND pattern. relaxor...
Abstract A recently emerged XRD-based cos α residual stress measurement method, which utilizes imaging plate detectors, has attracted special attention from both academia and industry. There are uncertainties about to extent the method could be used accuracy of measurements when analyzing industrial components. This work investigates by targeting four common types material structures for XRD experiments: preferred orientation microstructure (texture effect), coarse grain (coarse a...