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Materials Science and Engineering Faculty Research & Creative Works
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- Ferroelectric materials (4)
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Articles 1 - 14 of 14
Full-Text Articles in Engineering
Orientations Of Low-Energy Domain Walls In Perovskites With Oxygen Octahedral Tilts, Fei Xue, Yijia Gu, Linyun Liang, Yi Wang, Long-Qing Chen
Orientations Of Low-Energy Domain Walls In Perovskites With Oxygen Octahedral Tilts, Fei Xue, Yijia Gu, Linyun Liang, Yi Wang, Long-Qing Chen
Materials Science and Engineering Faculty Research & Creative Works
Many applications of ferroic materials, such as data storage and spintronics, are achieved through the control and manipulation of their domain wall (DW) orientations and configurations. Here we propose a rotational compatibility condition to identify low-energy DWs in perovskites with oxygen octahedral tilt instability. It is derived from the strong DW energy anisotropy arising from the rigidity and corner-sharing feature of the octahedral network. We analyze quantitatively the DWs in SrTiO3 and explain successfully the unusual ferroelectric DW width and energy in BiFeO3.
First-Principles Study Of 180⁰ Domain Walls In Batio₃: Mixed Bloch-Néel-Ising Character, Menglei Li, Yijia Gu, Yi Wang, Long-Qing Chen, Wenhui Duan
First-Principles Study Of 180⁰ Domain Walls In Batio₃: Mixed Bloch-Néel-Ising Character, Menglei Li, Yijia Gu, Yi Wang, Long-Qing Chen, Wenhui Duan
Materials Science and Engineering Faculty Research & Creative Works
The 180⁰ ferroelectric domain walls (FDWs) have long been regarded as purely Ising type in ferroelectrics, but recent theoretical works suggested that they can also have Néel- and/or Bloch-like rotations. Using a combination of first-principles calculations with phase-field simulations, we studied the 180⁰ FDWs on different crystallographic planes in prototypical ferroelectric perovskite BaTiO3. The polarization profiles of 180 FDWs on (100) and (410) planes revealed that the (100)- and (410)-FDWs both exhibit Néel-like character besides their intrinsic Ising character, while the (410)-FDW also simultaneously shows a Bloch-like oblique of ~6 nm, as a consequence of the deviation of …
An Investigation Of The Effect Of Direct Metal Deposition Parameters On The Characteristics Of The Deposited Layers, Tarak A. Amine, Joseph William Newkirk, Frank W. Liou
An Investigation Of The Effect Of Direct Metal Deposition Parameters On The Characteristics Of The Deposited Layers, Tarak A. Amine, Joseph William Newkirk, Frank W. Liou
Materials Science and Engineering Faculty Research & Creative Works
Multilayer direct laser deposition (DLD) is a fabrication process through which parts are fabricated by creating a molten pool into which metal powder is injected as particles. During fabrication, complex thermal activity occurs in different regions of the build; for example, newly deposited layers will reheat previously deposited layers. The objective of this study was to provide insight into the thermal activity that occurs during the DLD process. This work focused on the effect of the laser parameters of newly deposited layers on the microstructure and mechanical properties of the previously deposited layers in order to characterize these effects to …
Modulating Notochordal Differentiation Of Human Induced Pluripotent Stem Cells Using Natural Nucleus Pulposus Tissue Matrix, Yongxing Liu, M. N. Rahaman, B. Sonny Bal
Modulating Notochordal Differentiation Of Human Induced Pluripotent Stem Cells Using Natural Nucleus Pulposus Tissue Matrix, Yongxing Liu, M. N. Rahaman, B. Sonny Bal
Materials Science and Engineering Faculty Research & Creative Works
Human induced pluripotent stem cells (hiPSCs) can differentiate into notochordal cell (NC)-like cells when cultured in the presence of natural porcine nucleus pulposus (NP) tissue matrix. The method promises massive production of high-quality, functional cells to treat degenerative intervertebral discs (IVDs). Based on our previous work, we further examined the effect of cell-NP matrix contact and culture medium on the differentiation, and further assessed the functional differentiation ability of the generated NC-like. The study showed that direct contact between hiPSCs and NP matrix can promote the differentiation yield, whilst both the contact and non-contact cultures can generate functional NC-like cells. …
Monoclinic Phases Arising Across Thermal Inter-Ferroelectric Phase Transitions, Yijia Gu, Fei Xue, Shiming Lei, Tom T. A. Lummen, Jianjun Wang, For Full List Of Authors, See Publisher's Website.
Monoclinic Phases Arising Across Thermal Inter-Ferroelectric Phase Transitions, Yijia Gu, Fei Xue, Shiming Lei, Tom T. A. Lummen, Jianjun Wang, For Full List Of Authors, See Publisher's Website.
Materials Science and Engineering Faculty Research & Creative Works
Thermotropic phase boundaries (TPBs), as thermal analogs of morphotropic phase boundaries (MPBs), are associated with the thermal inter-ferroelectric phase transitions. Similar to an MPB, a TPB exhibits a characteristically flattened energy profile which favors polarization rotation, thus giving rise to a structurally bridging low-symmetry phase. We report on the kinetic process of thermal inter-ferroelectric phase transitions in BaTiO3 and KNbO3 using the phase-field method. The domain structures are found to play key roles in stabilizing the monoclinic phase. In simple domain structures, the monoclinic phase is a transient phase and cannot be stabilized into its neighboring phase regimes. …
Ceramic Welds, And A Method For Producing The Same, Greg Hilmas, William Fahrenholtz, Jeremy Lee Watts, Harlan James Brown-Shaklee
Ceramic Welds, And A Method For Producing The Same, Greg Hilmas, William Fahrenholtz, Jeremy Lee Watts, Harlan James Brown-Shaklee
Materials Science and Engineering Faculty Research & Creative Works
A method of producing a ceramic weld, including identifying a ceramic first surface and a ceramic second surface to be bonded together, maintaining a non-oxidizing atmosphere over the first and second surfaces, and engaging the first and second surfaces to define a joint. An arc is generated between an electrode and the joint to create a liquid phase, and the liquid phase is cooled to yield a solid fusion layer, wherein the first and second surfaces are joined in the fusion layer.
Flexoelectricity And Ferroelectric Domain Wall Structures: Phase-Field Modeling And Dft Calculations, Yijia Gu, Menglei Li, Anna N. Morozovska, Yi Wang, Eugene A. Eliseev, For Full List Of Authors, See Publisher's Website.
Flexoelectricity And Ferroelectric Domain Wall Structures: Phase-Field Modeling And Dft Calculations, Yijia Gu, Menglei Li, Anna N. Morozovska, Yi Wang, Eugene A. Eliseev, For Full List Of Authors, See Publisher's Website.
Materials Science and Engineering Faculty Research & Creative Works
We show that flexoelectric effect is responsible for the non-Ising character of a 180° ferroelectric domain wall. The wall, long considered being of Ising type, contains both Bloch- and Néel-type polarization components. Using the example of classic ferroelectric BaTiO3, and by incorporating the flexoelectric effect into a phase-field model, it is demonstrated that the flexoelectric effect arising from stress inhomogeneity around the domain wall leads to the additional Bloch and Néel polarization components. The magnitudes of these additional components are two or three magnitudes smaller than the Ising component, and they are determined by the competing depolarization and flexoelectric fields. …
The Properties And Structure Of Zinc Magnesium Phosphate Glasses, Charmayne E. Smith (Lonergan), Richard K. Brow
The Properties And Structure Of Zinc Magnesium Phosphate Glasses, Charmayne E. Smith (Lonergan), Richard K. Brow
Materials Science and Engineering Faculty Research & Creative Works
Zn-Mg-phosphate (ZMP) glasses, including those with the nominal molar compositions (50 - x)ZnO xMgO 50P2O5 (0 ≥ x ≥ 50) and (60 - y)ZnO yMgO 40P2O5(0 ≥ y ≥ 60), were prepared and properties such as density, refractive index, coefficient of thermal expansion and glass transition temperature (Tg), were measured. The glass transition temperature increases by 100-150 C and the room temperature dissolution rates in water decrease by 1-2 orders of magnitude when MgO replaces ZnO while maintaining a constant P2O5 content. Glass structures were characterized by Raman spectroscopy and …
Corrosion-Resistant Glasses For Steel Enamels, Richard K. Brow, Signo Tadeu Dos Reis, Michael L. Koenigstein, Genda Chen
Corrosion-Resistant Glasses For Steel Enamels, Richard K. Brow, Signo Tadeu Dos Reis, Michael L. Koenigstein, Genda Chen
Materials Science and Engineering Faculty Research & Creative Works
A cementitious composite material wherein glass-coated steel rods are positioned in a cementitious matrix. The glass composition for coating the steel reinforcing rods includes between about 33-45 weight percent SiO2, 13.5-19.5 weight percent B2O3, 3.5-4.6 weight percent Al2O3, 4.0-13.5 weight percent K2O, 5.5-15.5 weight percent ZrO2, 8.6-15.9 weight percent Na2O, 4.6-5.1 weight percent CaO, 0.6-0.7 weight percent MnO2, 1.0-1.0 weight percent NiO, and 1.0-1.1 weight percent CoO. The glass composition is typically in compression on the rods at ambient temperatures, has a …
The Structure And Properties Of Zinc Aluminophosphate Glasses, Charmayne E. Smith (Lonergan), Richard K. Brow, Lionel Montagne, Bertrand Revel
The Structure And Properties Of Zinc Aluminophosphate Glasses, Charmayne E. Smith (Lonergan), Richard K. Brow, Lionel Montagne, Bertrand Revel
Materials Science and Engineering Faculty Research & Creative Works
The glass forming region of the ZnO-Al2O3-P2O5 (ZAP) system was determined and the structures and properties of the glasses were characterized. For glasses with a constant O/P ratio, i.e., with similar average phosphate anion distributions, and with increasing alumina content, there is an increase in molar volume and glass transition temperature and a decrease in density and refractive index. The structures of the ZAP glasses were characterized by Raman spectroscopy, 31P and 27Al magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, and high pressure liquid chromatography (HPLC). Systematically shorter phosphate …
Nanostructured Dielectric Materials For High Energy Density Multilayer Ceramic Capacitors, Fatih Dogan, Alan Devoe, Ian Burn
Nanostructured Dielectric Materials For High Energy Density Multilayer Ceramic Capacitors, Fatih Dogan, Alan Devoe, Ian Burn
Materials Science and Engineering Faculty Research & Creative Works
A multilayer ceramic capacitor, having a plurality of electrode layers and a plurality of substantially titanium dioxide dielectric layers, wherein each respective titanium dioxide dielectric layer is substantially free of porosity, wherein each respective substantially titanium dioxide dielectric layer is positioned between two respective electrode layers, wherein each respective substantially titanium dioxide dielectric layer has an average grain size of between about 200 and about 400 nanometers, wherein each respective substantially titanium dioxide dielectric layer has maximum particle size of less than about 500 nanometers. Typically, each respective substantially titanium dioxide dielectric layer further includes at least one dopant selected …
Electric-Field Induced Ferromagnetic Phase In Paraelectric Antiferromagnets, Maya D. Glinchuk, Eugene A. Eliseev, Yijia Gu, Long-Qing Chen, Venkatraman Gopalan, Anna N. Morozovska
Electric-Field Induced Ferromagnetic Phase In Paraelectric Antiferromagnets, Maya D. Glinchuk, Eugene A. Eliseev, Yijia Gu, Long-Qing Chen, Venkatraman Gopalan, Anna N. Morozovska
Materials Science and Engineering Faculty Research & Creative Works
The phase diagram of a quantum paraelectric antiferromagnet EuTiO33 under an external electric field is calculated using Landau-Ginzburg-Devonshire theory. The application of an electric field E in the absence of strain leads to the appearance of a ferromagnetic (FM) phase due to the magnetoelectric (ME) coupling. At an electric field greater than a critical field, Ecr, the antiferromagnetic (AFM) phase disappears for all considered temperatures, and FM becomes the only stable magnetic phase. The calculated value of the critical field is close to the values reported recently by Ryan et al. [Nat. Commun. 4, 1334 (2013)10.1038/ncomms2329] …
A Novel Injectable Borate Bioactive Glass Cement As An Antibiotic Delivery Vehicle For Treating Osteomyelitis, Hao Ding, Cunju Zhao, Xu Cui, Yifei Gu, Weitao Jia, M. N. Rahaman, Yang Wang, Wenhai Huang, Changqing Zhang
A Novel Injectable Borate Bioactive Glass Cement As An Antibiotic Delivery Vehicle For Treating Osteomyelitis, Hao Ding, Cunju Zhao, Xu Cui, Yifei Gu, Weitao Jia, M. N. Rahaman, Yang Wang, Wenhai Huang, Changqing Zhang
Materials Science and Engineering Faculty Research & Creative Works
Background: A novel injectable cement composed of chitosan-bonded borate bioactive glass (BG) particles was evaluated as a carrier for local delivery of vancomycin in the treatment of osteomyelitis in a rabbit tibial model. Materials and Methods: The setting time, injectability, and compressive strength of the borate BG cement, and the release profile of vancomycin from the cement were measured in vitro. The capacity of the vancomycin-loaded BG cement to eradicate methicillin-resistant Staphylococcus aureus (MRSA)-induced osteomyelitis in rabbit tibiae in vivo was evaluated and compared with that for a vancomycin-loaded calcium sulfate (CS) cement and for intravenous injection of vancomycin. Results: …
Thermotropic Phase Boundaries In Classic Ferroelectrics, Tom T. A. Lummen, Yijia Gu, Jianjun Wang
Thermotropic Phase Boundaries In Classic Ferroelectrics, Tom T. A. Lummen, Yijia Gu, Jianjun Wang
Materials Science and Engineering Faculty Research & Creative Works
High-performance piezoelectrics are lead-based solid solutions that exhibit a so-called morphotropic phase boundary, which separates two competing phases as a function of chemical composition; as a consequence, an intermediate low-symmetry phase with a strong piezoelectric effect arises. In search for environmentally sustainable lead-free alternatives that exhibit analogous characteristics, we use a network of competing domains to create similar conditions across thermal inter-ferroelectric transitions in simple, lead-free ferroelectrics such as BaTiO3 and KNbO3. Here we report the experimental observation of thermotropic phase boundaries in these classic ferroelectrics, through direct imaging of low-symmetry intermediate phases that exhibit large enhancements …