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Articles 1 - 30 of 38
Full-Text Articles in Other Chemical Engineering
Note: A Simple Thermal Gradient Annealing Unit For The Treatment Of Thin Films, C. J. Metting, Johnathan K. Bunn, Ellen A. Underwood, Yihao Zhu, G. Koley, T. Crawford, Jason R. Hattrick-Simpers
Note: A Simple Thermal Gradient Annealing Unit For The Treatment Of Thin Films, C. J. Metting, Johnathan K. Bunn, Ellen A. Underwood, Yihao Zhu, G. Koley, T. Crawford, Jason R. Hattrick-Simpers
Faculty Publications
A gradient annealing cell has been developed for the high-throughput study of thermalannealing effects on thin-film libraries in different environments. The inexpensive gradientannealing unit permits temperature gradients as large as 28 °C/mm and can accommodate samples ranging in length from 13 mm to 51 mm. The system was validated by investigating the effects of annealing temperature on the crystallinity, resistivity, and transparency of tin-doped indium oxide deposited on a glass substrate by magnetron sputtering. The unit developed in this work will permit the rapid optimization of materials properties such as crystallinity, homogeneity, and conductivity across a variety of applications.
Applications Of High Throughput (Combinatorial) Methodologies To Electronic, Magnetic, Optical, And Energy-Related Materials, Martin L. Green, Ichiro Takeuchi, Jason R. Hattrick-Simpers
Applications Of High Throughput (Combinatorial) Methodologies To Electronic, Magnetic, Optical, And Energy-Related Materials, Martin L. Green, Ichiro Takeuchi, Jason R. Hattrick-Simpers
Faculty Publications
High throughput (combinatorial) materials science methodology is a relatively new research paradigm that offers the promise of rapid and efficient materials screening, optimization, and discovery. The paradigm started in the pharmaceutical industry but was rapidly adopted to accelerate materials research in a wide variety of areas. High throughput experiments are characterized by synthesis of a “library” sample that contains the materials variation of interest (typically composition), and rapid and localized measurement schemes that result in massive data sets. Because the data are collected at the same time on the same “library” sample, they can be highly uniform with respect to …
Capacity Fade Model For Spinel Limn2O4 Electrode, Yiling Dai, Long Cai, Ralph E. White
Capacity Fade Model For Spinel Limn2O4 Electrode, Yiling Dai, Long Cai, Ralph E. White
Faculty Publications
A mathematical model for the capacity fade of a LiMn2O4 (LMO) electrode is developed in this paper by including the acid attack on the active material and the solid electrolyte interphase (SEI) film formation on the LMO particle surface. The acid generated by the LiPF6 and the solvent decompositions are coupled to the manganese (Mn) dissolution. The decrease of the Li ion diffusion coefficient is involved as another contribution to the capacity fade, which is caused by the passive film formation on the active material surface. The effects of cell practical operation/fabrication conditions and kinetics of …
Quantifying Cell-To-Cell Variations In Lithium Ion Batteries, Shriram Santhanagopalan, Ralph E. White
Quantifying Cell-To-Cell Variations In Lithium Ion Batteries, Shriram Santhanagopalan, Ralph E. White
Faculty Publications
Lithium ion batteries have conventionally been manufactured in small capacities but large volumes for consumer electronics applications. More recently, the industry has seen a surge in the individual cell capacities, as well as the number of cells used to build modules and packs. Reducing cell-to-cell and lot-to-lot variations has been identified as one of the major means to reduce the rejection rate when building the packs as well as to improve pack durability. The tight quality control measures have been passed on from the pack manufactures to the companies building the individual cells and in turn to the components. This …
Giant Magnetostriction In Annealed Co1-XFeX Thin-Films, Dwight Hunter, Will Osborn, Ke Wang, Nataliya Kazantseva, Jason R. Hattrick-Simpers, Richard Suchoski, Ryota Takahashi, Marcus L. Young, Apurva Mehta, Leonid A. Bendersky, Same E. Lofland, Manfred Wuttig, Ichiro Takeuchi
Giant Magnetostriction In Annealed Co1-XFeX Thin-Films, Dwight Hunter, Will Osborn, Ke Wang, Nataliya Kazantseva, Jason R. Hattrick-Simpers, Richard Suchoski, Ryota Takahashi, Marcus L. Young, Apurva Mehta, Leonid A. Bendersky, Same E. Lofland, Manfred Wuttig, Ichiro Takeuchi
Faculty Publications
Chemical and structural heterogeneity and the resulting interaction of coexisting phases can lead to extraordinary behaviours in oxides, as observed in piezoelectric materials at morphotropic phase boundaries and relaxor ferroelectrics. However, such phenomena are rare in metallic alloys. Here we show that, by tuning the presence of structural heterogeneity in textured Co1−xFex thin films, effective magnetostriction λeff as large as 260 p.p.m. can be achieved at low-saturation field of ~10 mT. Assuming λ100 is the dominant component, this number translates to an upper limit of magnetostriction ofλ100≈5λeff >1,000 p.p.m. Microstructural analyses …
Optical Cell For Combinatorial In Situ Raman Spectroscopic Measurements Of Hydrogen Storage Materials At High Pressures And Temperatures, Jason R. Hattrick-Simpers, Wilbur S. Hurst, Sesha S. Srinivasan, James E. Maslar
Optical Cell For Combinatorial In Situ Raman Spectroscopic Measurements Of Hydrogen Storage Materials At High Pressures And Temperatures, Jason R. Hattrick-Simpers, Wilbur S. Hurst, Sesha S. Srinivasan, James E. Maslar
Faculty Publications
An optical cell is described for high-throughput backscattering Raman spectroscopic measurements of hydrogen storagematerials at pressures up to 10 MPa and temperatures up to 823 K. High throughput is obtained by employing a 60 mm diameter × 9 mm thick sapphire window, with a corresponding 50 mm diameter unobstructed optical aperture. To reproducibly seal this relatively large window to the cell body at elevated temperatures and pressures, a gold o-ring is employed. The sample holder-to-window distance is adjustable, making this cell design compatible with optical measurement systems incorporating lenses of significantly different focal lengths, e.g., microscope objectives and single element …
Single-Particle Model For A Lithium-Ion Cell: Thermal Behavior, Meng Guo, Godfrey Sikha, Ralph E. White
Single-Particle Model For A Lithium-Ion Cell: Thermal Behavior, Meng Guo, Godfrey Sikha, Ralph E. White
Faculty Publications
The single-particle model presented by Santhanagopalan et al. [ J. Power Sources , 156 , 620 (2006)] is extended to include an energy balance. The temperature dependence of the solid phase diffusion coefficient of the lithium in the intercalation particles, the electrochemical reaction rate constants, and the open circuit potentials (OCPs) of the positive and negative electrodes are included in the model. The solution phase polarization is approximated using a nonlinear resistance, which is a function of current and temperature. The model is used to predict the temperature and voltage profiles in a lithium-ion cell during galvanostatic operations. The single-particle …
Theoretical Analysis Of Stresses In A Lithium Ion Cell, Sindhuja Renganathan, Godfrey Sikha, Shriram Santhanagopalan, Ralph E. White
Theoretical Analysis Of Stresses In A Lithium Ion Cell, Sindhuja Renganathan, Godfrey Sikha, Shriram Santhanagopalan, Ralph E. White
Faculty Publications
A mathematical model to simulate the generation of mechanical stress during the discharge process in a dual porous insertion electrode cell sandwich comprised of lithium cobalt oxide and carbon is presented. The model attributes stress buildup within intercalation electrodes to two different aspects: changes in the lattice volume due to intercalation and phase transformation during the charge/discharge process. The model is used to predict the influence of cell design parameters such as thickness, porosity, and particle size of the electrodes on the magnitude of stress generation. The model developed in this study can be used to understand the mechanical degradation …
Maximizing The Life Of A Lithium-Ion Cell By Optimization Of Charging Rates, Saeed Khaleghi Rahimian, Sean Rayman, Ralph E. White
Maximizing The Life Of A Lithium-Ion Cell By Optimization Of Charging Rates, Saeed Khaleghi Rahimian, Sean Rayman, Ralph E. White
Faculty Publications
Using a dynamic optimization method, the optimum charge currents as a function of cycle number during cycling for the lithium-ion cell are obtained. A single particle physics-based model, which includes capacity fade, was applied to simulate the cell performance under low earth-orbit (LEO) cycling conditions. Useful cell life is defined as the number of cycles before the end of discharge voltage drops below 3.0 V or the cell discharge capacity becomes less than 20% of the original discharge capacity. The simulated useful cell life can be increased by ∼29.28% by varying the charge current.
The Effect Of Copt Crystallinity And Grain Texturing On Properties Of Exchange-Coupled Fe/Copt Systems, H. Oguchi, A. Zambano, M. Yu, Jason R. Hattrick-Simpers, D. Banerjee, Y. Liu, Z. L. Wang, J. P. Liu, S. E. Lofland, D. Josell, I. Takeuchi
The Effect Of Copt Crystallinity And Grain Texturing On Properties Of Exchange-Coupled Fe/Copt Systems, H. Oguchi, A. Zambano, M. Yu, Jason R. Hattrick-Simpers, D. Banerjee, Y. Liu, Z. L. Wang, J. P. Liu, S. E. Lofland, D. Josell, I. Takeuchi
Faculty Publications
The effect of the crystallinity and the grain texturing of CoPt hard layers on exchange coupled Fe/CoPt soft/hard magnetic systems was studied using gradient thickness multilayer thin films. We have studied the hard layer structures by transmission electron microscopy and x-ray diffraction, and characterized the exchange coupling interaction through magnetization loops obtained by the magneto-optical Kerr effect measurement. We found that exchange coupling strongly depends on the crystalline characteristics of the CoPt hard layer. There is correlation between the mixture of different grain orientations of the CoPt hard layer and coupling efficiency. In particular, interlayer coupling is enhanced when there …
An Infrared Imaging Method For High-Throughput Combinatorial Investigation Of Hydrogenation-Dehydrogenation And New Phase Formation Of Thin Films, H. Oguchi, Jason R. Hattrick-Simpers, I. Takeuchi, E. J. Heilweil, L. A. Bendersky
An Infrared Imaging Method For High-Throughput Combinatorial Investigation Of Hydrogenation-Dehydrogenation And New Phase Formation Of Thin Films, H. Oguchi, Jason R. Hattrick-Simpers, I. Takeuchi, E. J. Heilweil, L. A. Bendersky
Faculty Publications
We have developed an infrared imaging setup enabling in situ infrared images to be acquired, and expanded on capabilities of an infrared imaging as a high-throughput screening technique, determination of a critical thickness of a Pd capping layer which significantly blocks infrared emission from below, enhancement of sensitivity to hydrogenation and dehydrogenation by normalizing raw infrared intensity of a Mg thin film to an inert reference, rapid and systematic screening of hydrogenation and dehydrogenation properties of a Mg–Ni composition spread covered by a thickness gradient Pd capping layer, and detection of formation of a Mg2Si phase in a …
Reduction Of Model Order Based On Proper Orthogonal Decomposition For Lithium-Ion Battery Simulations, Long Cai, Ralph E. White
Reduction Of Model Order Based On Proper Orthogonal Decomposition For Lithium-Ion Battery Simulations, Long Cai, Ralph E. White
Faculty Publications
A reduced-order model (ROM) is developed using proper orthogonal decomposition (POD) for a physics-based lithium-ion battery model. The methodology to obtain the proper orthogonal modes and to analyze their optimality is included. The POD-based ROM for a lithium-ion battery is used to simulate a charge/discharge process and the behavior of a battery pack. Compared to the physics-based model, the computational time to solve the ROM is significantly less, and the two models show excellent agreement.
Combinatorial Investigation Of Magnetostriction In Fe-Fa And Fe-Ga-Al, Jason R. Hattrick-Simpers, Dwight Hunter, Corneliu M. Craciunescu, Kyu Sung Jang, Makoto Murakami, James Cullen, Manfred Wuttig, Ichiro Takeuchi, Samuel E. Lofland, Leonid Bendersky, Noble Woo, Robert Bruce Vandover, Toshiya Takahashi, Yasubumi Furuya
Combinatorial Investigation Of Magnetostriction In Fe-Fa And Fe-Ga-Al, Jason R. Hattrick-Simpers, Dwight Hunter, Corneliu M. Craciunescu, Kyu Sung Jang, Makoto Murakami, James Cullen, Manfred Wuttig, Ichiro Takeuchi, Samuel E. Lofland, Leonid Bendersky, Noble Woo, Robert Bruce Vandover, Toshiya Takahashi, Yasubumi Furuya
Faculty Publications
A high-throughput high-sensitivity optical technique for measuringmagnetostriction of thin-film composition-spread samples has been developed. It determines the magnetostriction by measuring the induced deflection of micromachined cantilever unimorph samples. Magnetostrictionmeasurements have been performed on as-deposited Fe–Ga and Fe–Ga–Al thin-film composition spreads. The thin-film Fe–Ga spreads display a similar compositional variation of magnetostriction as bulk. A previously undiscovered peak in magnetostriction at low Ga content was also observed and attributed to a maximum in the magnetocrystalline anisotropy. Magnetostrictive mapping of the Fe–Ga–Al ternary system reveals the possibility of substituting up to 8at.%Al in Fe70Ga30 without significant degradation of magnetostriction.
Thermal Model For A Li-Ion Cell, Karthikeyan Kumaresan, Godfrey Sikha, Ralph E. White
Thermal Model For A Li-Ion Cell, Karthikeyan Kumaresan, Godfrey Sikha, Ralph E. White
Faculty Publications
A thermal model for a lithium-ion cell is presented and used to predict discharge performance at different operating temperatures. The results from the simulations are compared to experimental data obtained from lithium-ion pouch cells. The model includes a set of parameters (and their concentration and temperature dependencies) that has been obtained for a lithium-ion cell composed of a mesocarbon microbead anode, LiCoO2 cathode in 1 M LiPF6 salt, in a mixture of ethylene carbonate, propylene carbonate, ethyl-methyl carbonate, and diethyl carbonate electrolyte. The parameter set was obtained by comparing the model predictions to the experimental discharge profiles obtained …
Parameter Estimation And Life Modeling Of Lithium-Ion Cells, Shriram Santhanagopalan, Qi Zhang, Karthikeyan Kumaresan, Ralph E. White
Parameter Estimation And Life Modeling Of Lithium-Ion Cells, Shriram Santhanagopalan, Qi Zhang, Karthikeyan Kumaresan, Ralph E. White
Faculty Publications
Lithium-ion pouch cells were cycled at five different temperatures (5, 15, 25, 35, and 45°C ), and rate capability studies were performed after every hundred cycles. The data were used with a simple physics-based model to estimate parameters that capture the capacity fade in the cell, with cycling. The weight of active material within each electrode was estimated as a function of time, using rate capability data at the C/33 rate. The C-rate for these cells is 1.656 A. The capacity fade due to the loss of active material and that due to the loss of cyclable lithium …
A Mathematical Model For A Lithium–Sulfur Cell, Karthikeyan Kumaresan, Yuriy Mikhaylik, Ralph E. White
A Mathematical Model For A Lithium–Sulfur Cell, Karthikeyan Kumaresan, Yuriy Mikhaylik, Ralph E. White
Faculty Publications
A mathematical model is presented for a complete lithium–sulfur cell. The model includes various electrochemical and chemical (precipitation) reactions, multicomponent transport phenomena in the electrolyte, and the charge transfer within and between solid and liquid phases. A change in the porosity of the porous cathode and separator due to precipitation reactions is also included in the model. The model is used to explain the physical reasons for the two-stage discharge profiles that are typically obtained for lithium–sulfur cells.
Analytical Expression For The Impedance Response For A Lithium-Ion Cell, Godfrey Sikha, Ralph E. White
Analytical Expression For The Impedance Response For A Lithium-Ion Cell, Godfrey Sikha, Ralph E. White
Faculty Publications
An analytical expression to predict the impedance response of a dual insertion electrode cell (insertion electrodes separated by an ionically conducting membrane) is presented. The expression accounts for the reaction kinetics and double-layer adsorption processes at the electrode-electrolyte interface, transport of electroactive species in the electrolyte phase, and insertion of species in the solid phase of the insertion electrodes. The accuracy of the analytical expression is validated by comparing the impedance response predicted by the expression to the corresponding numerical solution. The analytical expression is used to predict the impedance response of a lithium-ion cell consisting of a porous LiCoO …
Enhanced Dielectric Properties In Single Crystal-Like Bifeo3 Thin Films Grown By Flux-Mediated Epitaxy, S.-H. Lim, M. Murakami, J. H. Yang, S.-Y. Young, Jason R. Hattrick-Simpers, M. Wuttig, L. G. Salamanca-Riba, I. Takeuchi
Enhanced Dielectric Properties In Single Crystal-Like Bifeo3 Thin Films Grown By Flux-Mediated Epitaxy, S.-H. Lim, M. Murakami, J. H. Yang, S.-Y. Young, Jason R. Hattrick-Simpers, M. Wuttig, L. G. Salamanca-Riba, I. Takeuchi
Faculty Publications
We have fabricated single crystal-like BiFeO3 (BFO) thin films by flux-mediated epitaxy using pulsed laser deposition(PLD). The Bi–Cu–O flux composition and its thickness were optimized using composition spread, thickness gradient, and temperature gradient libraries. The optimized BFO thin films grown with this technique showed larger grain size of ∼2μm and higher dielectric constant in the range of 260–340 than those for standard PLD grown films. In addition, the leakage current density of the films was reduced by two orders of magnitude compared to that of standard PLD grown films.
Rapid Structural Mapping Of Ternary Metallic Alloy Systems Using The Combinatorial Approach And Cluster Analysis, C. J. Long, Jason R. Hattrick-Simpers, M. Murakami, R. C. Srivastava, I. Takeuchi, V. L. Karen, X. Li
Rapid Structural Mapping Of Ternary Metallic Alloy Systems Using The Combinatorial Approach And Cluster Analysis, C. J. Long, Jason R. Hattrick-Simpers, M. Murakami, R. C. Srivastava, I. Takeuchi, V. L. Karen, X. Li
Faculty Publications
We are developing a procedure for the quick identification of structural phases in thin film composition spread experiments which map large fractions of compositional phase diagrams of ternary metallic alloy systems. An in-house scanning x-ray microdiffractometer is used to obtain x-ray spectra from 273 different compositions on a single composition spread library. A cluster analysissoftware is then used to sort the spectra into groups in order to rapidly discover the distribution of phases on the ternary diagram. The most representative pattern of each group is then compared to a database of known structures to identify known phases. Using this method, …
Accelerated Testing Method For Pem Fuel Cell Based Uninterrupted Power Supply Systems, Xinyu Huang, Xiaofeng Wang
Accelerated Testing Method For Pem Fuel Cell Based Uninterrupted Power Supply Systems, Xinyu Huang, Xiaofeng Wang
Faculty Publications
Proton exchange membrane fuel cell based power systems are on the verge of commercialization for a number of niche applications where batteries are traditionally used. Uninterrupted power supply (UPS) for wireless communication towers and broadband network relay utilities is one of the targeted application of fuel cell power systems with capacity ranging from one to serveral kilowatts. It is believed that fuel cell based UPS systems can offer considerable advantage when extended backup time is desirable. In order to replace the well-known battery based UPS systems, the reliability and perofrmance of fuel cell based UPS system need to be thoroughly …
Moving Boundary Model For The Discharge Of A Licoo2 Electrode, Qi Zhang, Ralph E. White
Moving Boundary Model For The Discharge Of A Licoo2 Electrode, Qi Zhang, Ralph E. White
Faculty Publications
A moving boundary model in a spherical LiCoO2 particle is presented to account for the diffusion controlled phase transition in LiCoO2 solid particles, and this model is incorporated into a porous electrode model for the LiCoO2 electrode. The simulation results agree well with the experimental data of a LiCoO2 electrode. A study of the flux distribution in the porous electrode shows that the phase transition phenomenon in the LiCoO2particles has a significant effect on the flux distribution by changing the solid phase diffusion resistance in the particles.
Simulation Of Polarization Curves For Oxygen Reduction Reaction In 0.5 M H2So4 At A Rotating Ring Disk Electrode, Qingbo Dong, Shriram Santhanagopalan, Ralph E. White
Simulation Of Polarization Curves For Oxygen Reduction Reaction In 0.5 M H2So4 At A Rotating Ring Disk Electrode, Qingbo Dong, Shriram Santhanagopalan, Ralph E. White
Faculty Publications
A cylindrical two-dimensional model based on the Nernst–Planck equations, the Navier–Stokes equation, and the continuity equation is used to simulate the oxygen reduction reaction in 0.5MH2SO4 at a rotating ring disk electrode. Concentration distributions and a potential profile are obtained as a function of the axial and radial distances from the center of the electrode surface. Polarization curves are simulated to interpret experimental results by studying various reaction mechanisms, i.e., the four-electron-transfer reduction of oxygen, the two-electron-transfer reduction of oxygen, a combination of the above two reactions, mechanisms with reduction of peroxide to water, and/or the heterogeneous …
Demonstration Of Magnetoelectric Scanning Probe Microscopy, Jason R. Hattrick-Simpers, Liyang Dai, Manfred Wuttig, Ichiro Takeuchi, Eckhard Quandt
Demonstration Of Magnetoelectric Scanning Probe Microscopy, Jason R. Hattrick-Simpers, Liyang Dai, Manfred Wuttig, Ichiro Takeuchi, Eckhard Quandt
Faculty Publications
A near-field room temperature scanning magnetic probe microscope has been developed using a laminated magnetoelectric sensor. The simple trilayer longitudinal-transverse mode sensor, fabricated using Metglas as the magnetostrictive layer and polyvinylidene fluoride as the piezoelectric layer, shows an ac field sensitivity of 467±3μV∕Oe in the measured frequency range of 200Hz–8kHz. The microscope was used to image a 2mm diameter ring carrying an ac current as low as 10−5A. ac fields as small as 3×10−10T have been detected.
The Microstructure And Grain Size Of Jet Electroplated Copper Films In Damascene Trench Features, Andrew Tzanavaras, Gregory Young, Stacy H. Gleixner
The Microstructure And Grain Size Of Jet Electroplated Copper Films In Damascene Trench Features, Andrew Tzanavaras, Gregory Young, Stacy H. Gleixner
Faculty Publications
The brightening additive level and dc current density of electroplating baths are two parameters that affect the gap-filling capability and the degree of impurity incorporation in electroplated copper films. Additive incorporation can inhibit grain growth during the room temperature recrystallization process and therefore affect the final grain size. This investigation explores the grain size and microstructure of dc jet-electroplated copper films in 0.35 and 0.50μm Damascene trenches as a function of current density and brightening additive level after first receiving a high-temperature anneal. Unlike a previous study that explored these variables in blanket Cu films [ J. Electrochem. Soc. , …
Combinatorial Study Of Ni-Ti-Pt Ternary Metal Gate Electrodes On Hfo2 For The Advanced Gate Stack, K.-S. Chang, M. L. Green, J. Suehle, E. M. Vogel, H. Xiong, Jason R. Hattrick-Simpers, I. Takeuchi, O. Famodu, K. Ohmori, P. Ahmet, T. Chikyow, P. Majhi, B.-H. Lee, M. Gardner
Combinatorial Study Of Ni-Ti-Pt Ternary Metal Gate Electrodes On Hfo2 For The Advanced Gate Stack, K.-S. Chang, M. L. Green, J. Suehle, E. M. Vogel, H. Xiong, Jason R. Hattrick-Simpers, I. Takeuchi, O. Famodu, K. Ohmori, P. Ahmet, T. Chikyow, P. Majhi, B.-H. Lee, M. Gardner
Faculty Publications
The authors have fabricated combinatorial Ni–Ti–Pt ternary metal gate thin film libraries on HfO2 using magnetron co-sputtering to investigate flatband voltage shift (ΔVfb) , work function (Φm) , and leakage current density (JL) variations. A more negative ΔVfb is observed close to the Ti-rich corner than at the Ni- and Pt-rich corners, implying smaller Φm near the Ti-rich corners and higher Φm near the Ni- and Pt-rich corners. In addition, measured JL values can be explained consistently with the observed Φm variations. Combinatorial methodologies prove to be useful …
The Grain Size And Microstructure Of Jet-Electroplated Damascene Copper Films, Stacy H. Gleixner, Andrew Tzanavaras, Gregory Young
The Grain Size And Microstructure Of Jet-Electroplated Damascene Copper Films, Stacy H. Gleixner, Andrew Tzanavaras, Gregory Young
Faculty Publications
Electroplated damascene copper is rapidly replacing aluminum-copper alloys for on-chip interconnect metallization in advanced ultralarge scale integrated (ULSI) semiconductor devices. In addition to a high degree of (111) crystallographic texture, large defect-free grains are desired to enhance the performance and reliability of copper interconnects in such devices. The brightening additive level and dc current density of electroplating baths are two parameters that affect the process gap-filling capability and the degree of additive incorporation in these copper films. Additive incorporation can inhibit grain growth during the room-temperature recrystallization process and therefore affect the final grain size in electroplated copper films. This …
Data Management And Visualization Of X-Ray Diffraction Spectra From Thin Film Ternary Composition Spreads, I. Takeuchi, C. J. Long, O. O. Famodu, M. Murakami, Jason R. Hattrick-Simpers, G. W. Rubloff, M. Stukowski, K. Rajan
Data Management And Visualization Of X-Ray Diffraction Spectra From Thin Film Ternary Composition Spreads, I. Takeuchi, C. J. Long, O. O. Famodu, M. Murakami, Jason R. Hattrick-Simpers, G. W. Rubloff, M. Stukowski, K. Rajan
Faculty Publications
We discuss techniques for managing and visualizing x-ray diffraction spectrum data for thin film composition spreads which map large fractions of ternary compositional phase diagrams. An in-house x-ray microdiffractometer is used to obtain spectra from over 500 different compositions on an individual spread. The MATLAB software is used to quickly organize the data and create various plots from which one can quickly grasp different information regarding structural and phase changes across the composition spreads. Such exercises are valuable in rapidly assessing the “overall” picture of the structural evolution across phase diagrams before focusing in on specific composition regions for detailed …
Interphase Exchange Coupling In Fe/Sm-Co Bilayers With Gradient Fe Thickness, Ming-Hui Yu, Jason R. Hattrick-Simpers, Ichiro Takeuchi, Jing Li, Z. L. Wang, J. P. Liu, S. E. Lofland, Somdev Tyagi, J. W. Freeland, D. Giubertoni, M. Bersani, M. Anderle
Interphase Exchange Coupling In Fe/Sm-Co Bilayers With Gradient Fe Thickness, Ming-Hui Yu, Jason R. Hattrick-Simpers, Ichiro Takeuchi, Jing Li, Z. L. Wang, J. P. Liu, S. E. Lofland, Somdev Tyagi, J. W. Freeland, D. Giubertoni, M. Bersani, M. Anderle
Faculty Publications
We have fabricated Fe∕Sm–Co bilayers with gradient Fe thicknesses in order to systematically study the dependence of exchange coupling on the thickness of the Fe layer. The Fe layer was deposited at two different temperatures (150 and 300°C) to study the effect of deposition temperature on the exchange coupling. Magneto-optical Kerr effect and x-ray magnetic circular dichroism (XMCD) have been employed as nondestructive rapid characterization tools to map the magnetic properties of the gradient samples. Systematic enhancement in exchange coupling between the soft layer and the hard layer is observed as the soft layer thickness is decreased. Separate exchange couplings …
Multimode Quantitative Scanning Microwave Microscopy Of In Situ Grown Epitaxial Ba1-XSrXTio3 Composition Spreads, K. S. Chang, M. Aronova, O. Famodu, I. Takeuchi, S. E. Lofland, Jason R. Hattrick-Simpers, H. Chang
Multimode Quantitative Scanning Microwave Microscopy Of In Situ Grown Epitaxial Ba1-XSrXTio3 Composition Spreads, K. S. Chang, M. Aronova, O. Famodu, I. Takeuchi, S. E. Lofland, Jason R. Hattrick-Simpers, H. Chang
Faculty Publications
We have performed variable-temperature multimode quantitative microwavemicroscopy of in situepitaxial Ba1−xSrxTiO3 thin-film composition spreads fabricated on (100) LaA1O3 substrates. Dielectric properties were mapped as a function of continuously varying composition from BaTiO3 to SrTiO3. We have demonstrated nondestructive temperature-dependent dielectric characterization of local thin-film regions. Measurements are simultaneously taken at multiple resonant frequencies of the microscope cavity. The multimode measurements allow frequency dispersion studies. We observe strong composition-dependent dielectric relaxation in Ba1−xSrxTiO3 at microwave frequencies.
Derivation Of An Analytical Model To Calculate Junction Depth In Hgcdte Photodiodes, Stacy H. Gleixner, H. G. Robinson, C. R. Helms
Derivation Of An Analytical Model To Calculate Junction Depth In Hgcdte Photodiodes, Stacy H. Gleixner, H. G. Robinson, C. R. Helms
Faculty Publications
Presents an enhanced analytical model to calculate junction depth and Hg interstitial profile during n-on-p junction formation in HgCdTe photodiodes. Detailed information on the enhanced model; Function of the model; Information on HgCdTe; Detailed information on how the model was obtained.