Cerium oxide nanomaterials (nanoceria, CNMs) are receiving increased attention from the research community due to their unique chemical properties, most prominent of which is ability alternate between Ce3+ and Ce4+ oxidation states. While many analytical techniques methods have been employed characterize amounts present (Ce3+/Ce4+ ratio) within nanoceria materials, to-date no studies used multiple complementary tools (orthogonal analysis) with technique-independent state controls for...

This paper attempts to improve upon the range of applicability and predictability empirical highly accelerated lifetime testing (HALT) equation that has been traditionally used estimate time dependent breakdown strength performance in multilayer ceramic capacitors (MLCC) integrated thin film capacitor structures. The present traditional HALT shows evidence being limited dielectric layers under high fields, for example, capacitance MLCCs. When equations are applied MLCCs with higher operating...

Low‐temperature conductivity mechanisms were identified in acceptor‐doped SrTiO 3 single crystals quenched from high temperatures under reducing conditions. Impedance spectroscopy measurements made on samples of the prototypical perovskite structure doped with iron provided a framework for creating complete model well‐defined point defect system. The dominant mechanism room‐temperature range was as being controlled by oxygen vacancy hopping. activation energy migration, an often debated...

Defect dipoles are significant point defects in perovskite oxides as a result of their impact on oxygen vacancy dynamics. Electron paramagnetic resonance (EPR) was used to investigate the local defect structure single crystal BaTiO3 doped with manganese. These results, along re-analysis literature data, do not support conclusion that transition metal-oxygen nearest neighbor (MnTi″−VO••)× ferroelectric majority centers previously reported. Local symmetry analysis zero-field splitting term...

Abstract A compact cold sintering stage was constructed to densify ceramic samples in capillary tubes for the purpose of conducting situ experiments designed elucidate fundamental mechanisms. The used successfully composed ZnO/CH₃COOH mixtures under a range pressures (25–175 MPa) over modest temperature (room 150°C) (0.75 mm inner diameter). progression process ZnO monitored by both piston displacement and camera. These measurements allowed strain rate fluid extraction during densification...

We report a microresonator platform that allows room temperature detection of electron spins in volumes on the order 100 pl, and demonstrate its utility to study low levels dopants perovskite oxides. exploit toroidal moment planar anapole, using single unit an anapole metamaterial architecture produce microwave resonance exhibiting spatially confined magnetic field hotspot simultaneously high quality-factor (Q-factor). To broad implementability this design scalability higher frequencies, we...

Laser triggered, megavolt, megampere gas switches are frequently utilized to synchronize multiple pulsed power driver modules for inertial-confinement fusion, isentropic compression, and radiation physics experiments. The device developed the 36 of refurbished accelerator at Sandia National Laboratories is a 5.4 MV, 700 kA, sulfur-hexafluoride () filled, laser triggered switch. At this operating level, switch jitter 5 ns, prefire rate less than 0.1%, average optic lifetime greater 200 shots,...

It is demonstrated that a transition metal redox‐active ion can exhibit amphoteric dopant substitution in the SrTiO 3 perovskite lattice. In stoichiometric , manganese preferably accommodated through isovalent as Mn 2+ on strontium site and 4+ titanium site. Previous studies have suggested either type of possible for compositions with tailored Sr/Ti stoichiometry. Using electron paramagnetic resonance (EPR) spectroscopy, occupancy dilute concentrations investigated function ratio. The tuned...

Low temperature conductivity mechanisms were identified in acceptor‐doped BaTiO 3 single crystals equilibrated and quenched from high under different oxygen partial pressures. A range of acceptor ionization states into samples doped with manganese or iron. Using an appropriate equivalent circuit to interpret impedance spectroscopy data, room the crystal identified, permittivity/temperature dependence was also shown be self‐consistent nature a first‐order ferroelectric phase transition. The...

Abstract Perovskite‐like NaNbO 3 ‐Bi 1/3 NbO solid solutions are studied to understand the interactions between octahedral rotations, which dominate structural behavior of and displacive disorder Bi present in . Models instantaneous structures for representative compositions obtained by refining atomic coordinates against X‐ray total scattering extended X‐ray‐absorption fine structure data, with additional input from transmission electron microscopy. A mixture distinct cations vacancies on...

The methodology for experimentally verifying the point-defect chemistry (site of substitution, valence, and charge-compensation mechanisms) in manganese-doped SrTiO3 ceramics is presented dilute nondilute dopant concentrations. Experimental theoretical techniques have strengths weaknesses depending upon defect types concentrations, so a combinatorial-characterization approach required. Using electron-paramagnetic resonance X-ray-absorption fine-structure measurements combined with density...

Abstract We report on our investigation of structural defect and strain formation in electrodegraded reduced oxidized, Fe ‐doped SrTiO 3 (Fe: STO ) single crystals using optical second harmonic generation ( SHG confocal Raman spectroscopy. spectra reveal electrochemical inhomogeneity resulting from the 4+ /oxygen ion 3+ vacancy aggregation sites along degraded anode cathode interfaces, respectively. show that mixed /Fe states gradients are generated across color fronts. These results, as...

Abstract The first in situ characterization of the pore morphology evolution during cold sintering process (CSP) is presented using small‐angle X‐ray scattering methods. For practical reasons, measurements have been made on a model system, KH 2 PO 4 (KDP). signal revealed striking behavior that could be modeled with nanoscale structural features associated dissolution and reprecipitation KDP close to grain/pore interface CSP. prospects for future more quantitative experiments under range...

We report on the detection of structural inhomogeneity across anode and cathode interfaces in electrically degraded reduced oxidized Fe-doped SrTiO3 (Fe:STO) single crystals by optical second harmonic generation (SHG) spectroscopy. SHG spectra were collected from several regions both Fe:STO crystals. identify formation defect concentration gradients along interfaces. While broken symmetries decrease outer region towards central anode, opposite trend is seen anode. These results are...

Abstract A eutectoid phase transformation was exhibited by the perovskite CeCrO 3 when heated in air. The kinetics of reaction, microstructure product, and mechanisms were studied using thermogravimetric analysis, X‐ray Raman spectroscopy, diffraction, electron microscopy. Fluorite CeO 2 corundum Cr O formed from decomposition . particles porous polycrystalline, a consequence nucleation, growth, impingent domains on particles. Anisotropic growth is indicated morphology grains, while single...

Abstract We report the results of an international interlaboratory study flexural strength alumina fabricated across six laboratories using vat photopolymerization ceramic additive manufacturing (AM) technology. The mechanical testing all specimens, 142 in total, was performed at National Institute Standards and Technology (NIST) according to well‐established four‐point bending method standardized for traditional ceramics. Overall, existing ASTM standard bend proved adequate AM ceramics,...

Abstract A charge-based deep level transient spectroscopy (Q-DLTS) method is applied to provide insights into the electronic behavior near grain boundaries and may new mechanisms such as fatigue, degradation, dielectric aging, breakdown. Here, we tested Q-DLTS in both a ZnO varistor material Fe-doped SrTiO 3 materials. Comparisons are made other data on varistors, obtain very good agreement for energy levels. The status of traps dielectrics has been investigated where relaxation was...

We report on the detection of electric field–induced second harmonic generation (EFISHG) from anode interfaces reduced and oxidized Fe-doped SrTiO3 (Fe:STO) single crystals. For crystal, we observe steady enhancements susceptibility components as imposed dc-voltage increases. The are attributed to a field-stabilized electrostriction, leading Fe:Ti-O bond stretching bending in Fe:Ti-O6 octahedra. no obvious structural changes observed below 16 kV/cm. Above kV/cm, sharp enhancement...

${\mathrm{BaZrO}}_{3}$ is reportedly one of few perovskites that retain an ideal cubic structure down to 0 K even though its ground state as predicted by first-principles calculations has remained contentious. Here, we combine electron diffraction with total neutron scattering measured on ceramic samples at cryogenic temperatures demonstrate below 80 K, this compound undergoes a structural change associated the onset correlated out phase rotations ${[\mathrm{ZrO}}_{6}]$ octahedra. The...

In order for ceramic additive manufacturing (AM) to achieve its full potential, it is increasingly important develop a more rigorous understanding of fundamental phenomena that govern the kinetics and thermodynamics AM processes. case build processes, such as direct ink write extrusion, methods densifying resulting green-body product need be considered complement efficiencies ceramics AM, itself. One densification route, at least monolithic components, built layer-by-layer, offered by...

Summary form only given. The Z machine at Sandia National Laboratories is a thirty six module pulsed power driver utilized for the study of inertial confinement fusion, isentropic compression experiments, and high density physics. Currently it undergoing an upgrade, called Z-Refurbishment (ZR). upgraded requires gas switches to be capable low jitter voltage switching, deliver energy load. final command-triggered switch in SF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML"...