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Full-Text Articles in Electrical and Computer Engineering

Applications Of High Throughput Screening Tools For Thermoelectric Materials, W. Wong-Ng, H. Joress, J. Martin, Y. Yan, M. Otani, E. Thomas, M. Green, Jason Hattrick-Simpers Mar 2015

Applications Of High Throughput Screening Tools For Thermoelectric Materials, W. Wong-Ng, H. Joress, J. Martin, Y. Yan, M. Otani, E. Thomas, M. Green, Jason Hattrick-Simpers

Jason R. Hattrick-Simpers

No abstract provided.

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The Effect Of Copt Crystallinity And Grain Texturing On Properties Of Exchange-Coupled Fe/Copt Systems, H. Oguchi, A. Zambano, M. Yu, Jason Hattrick-Simpers, D. Banerjee, Y. Liu, Z. Wang, J. Liu, S. Lofland, D. Josell, I. Takeuchi Mar 2015

The Effect Of Copt Crystallinity And Grain Texturing On Properties Of Exchange-Coupled Fe/Copt Systems, H. Oguchi, A. Zambano, M. Yu, Jason Hattrick-Simpers, D. Banerjee, Y. Liu, Z. Wang, J. Liu, S. Lofland, D. Josell, I. Takeuchi

Jason R. Hattrick-Simpers

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 …

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Combinatorial Study Of Ni-Ti-Pt Ternary Metal Gate Electrodes On Hfo2 For The Advanced Gate Stack, K.-S. Chang, M. Green, J. Suehle, E. Vogel, H. Xiong, Jason Hattrick-Simpers, I. Takeuchi, O. Famodu, K. Ohmori, P. Ahmet, T. Chikyow, P. Majhi, B.-H. Lee, M. Gardner Mar 2015

Combinatorial Study Of Ni-Ti-Pt Ternary Metal Gate Electrodes On Hfo2 For The Advanced Gate Stack, K.-S. Chang, M. Green, J. Suehle, E. Vogel, H. Xiong, Jason Hattrick-Simpers, I. Takeuchi, O. Famodu, K. Ohmori, P. Ahmet, T. Chikyow, P. Majhi, B.-H. Lee, M. Gardner

Jason R. Hattrick-Simpers

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 in surveying the large compositional space of ternary alloymetal gate electrode systems.

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Interphase Exchange Coupling In Fe/Sm-Co Bilayers With Gradient Fe Thickness, Ming-Hui Yu, Jason Hattrick-Simpers, Ichiro Takeuchi, Jing Li, Z. Wang, J. Liu, S. Lofland, Somdev Tyagi, J. Freeland, D. Giubertoni, M. Bersani, M. Anderle Mar 2015

Interphase Exchange Coupling In Fe/Sm-Co Bilayers With Gradient Fe Thickness, Ming-Hui Yu, Jason Hattrick-Simpers, Ichiro Takeuchi, Jing Li, Z. Wang, J. Liu, S. Lofland, Somdev Tyagi, J. Freeland, D. Giubertoni, M. Bersani, M. Anderle

Jason R. Hattrick-Simpers

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 …

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High-Throughput Screening Of Shape Memory Alloy Thin-Film Spreads Using Nanoindentation, Arpit Dwivedi, Thomas Wyrobek, Oden Warren, Jason Hattrick-Simpers, Olubenga Famodu, Ichiro Takeuchi Mar 2015

High-Throughput Screening Of Shape Memory Alloy Thin-Film Spreads Using Nanoindentation, Arpit Dwivedi, Thomas Wyrobek, Oden Warren, Jason Hattrick-Simpers, Olubenga Famodu, Ichiro Takeuchi

Jason R. Hattrick-Simpers

We have demonstrated the utility of nanoindentation as a rapid characterization tool for mapping shape memoryalloy compositions in combinatorial thin-film libraries. Nanoindentation was performed on Ni–Mn–Al ternary composition spreads. The indentation hardness and the reduced elastic modulus were mapped across a large fraction of the ternary phase diagram. The large shape memoryalloy composition region, located around the Heusler composition (Ni2MnAl), was found to display significant departure in these mechanical properties from the rest of the composition spread. In particular, the modulus and the hardness values are lower for the martensite region than those of the rest of the phase diagram.

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A Semi-Empirical Model For Tilted-Gun Planar Magnetron Sputtering Accounting For Chimney Shadowing, Johnathan Bunn, C. Metting, Jason Hattrick-Simpers Mar 2015

A Semi-Empirical Model For Tilted-Gun Planar Magnetron Sputtering Accounting For Chimney Shadowing, Johnathan Bunn, C. Metting, Jason Hattrick-Simpers

Jason R. Hattrick-Simpers

No abstract provided.

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Recent Developments In Thermoelectric Metrology At Nist, W. Wong-Ng, J. Martin, E. Thomas, M. Otani, N. Lowhorn, M. Green, G. Liu, Y. Yan, Jason Hattrick-Simpers, T. Tran Mar 2015

Recent Developments In Thermoelectric Metrology At Nist, W. Wong-Ng, J. Martin, E. Thomas, M. Otani, N. Lowhorn, M. Green, G. Liu, Y. Yan, Jason Hattrick-Simpers, T. Tran

Jason R. Hattrick-Simpers

No abstract provided.

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Exploration Of Magnetoelectric Thin-Film Sensors Using Supperlattice Composition Spreads, K.-S. Chang, M. Aronova, C. Gao, C. Lin, Jason Hattrick-Simpers, M. Murakami, I. Takeuchi Mar 2015

Exploration Of Magnetoelectric Thin-Film Sensors Using Supperlattice Composition Spreads, K.-S. Chang, M. Aronova, C. Gao, C. Lin, Jason Hattrick-Simpers, M. Murakami, I. Takeuchi

Jason R. Hattrick-Simpers

No abstract provided.

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Characterization Of Magnetic Degradation Mechanism In A High Neutron-Flux Environment, Adib Samin, Jie Qiu, Jason Hattrick-Simpers, Liyang Dai-Hattrick, Yuan Zheng, Lei Cao Mar 2015

Characterization Of Magnetic Degradation Mechanism In A High Neutron-Flux Environment, Adib Samin, Jie Qiu, Jason Hattrick-Simpers, Liyang Dai-Hattrick, Yuan Zheng, Lei Cao

Jason R. Hattrick-Simpers

No abstract provided.

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Combinatorial Study Of Thin Film Metal Hydride By Prompt Gamma Activation Analysis, L. Cao, Jason Hattrick-Simpers, R. Bindel, R. Bindel, B. Tomlin, R. Zeisler, R. Paul, L. Bendersky, R. Downing Mar 2015

Combinatorial Study Of Thin Film Metal Hydride By Prompt Gamma Activation Analysis, L. Cao, Jason Hattrick-Simpers, R. Bindel, R. Bindel, B. Tomlin, R. Zeisler, R. Paul, L. Bendersky, R. Downing

Jason R. Hattrick-Simpers

No abstract provided.

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Combinatorial Search Of Thermoelastic Shape-Memory Alloys With Extremely Small Hysteresis Width, Jun Cui, Yong Chu, Olugbenga Famodu, Yasubumi Furuya, Jason Hattrick-Simpers, Richard James, Alfred Ludwig, Sigurd Thienhaus, Manfred Wuttig, Zhiyong Zhang, Ichiro Takeuchi Mar 2015

Combinatorial Search Of Thermoelastic Shape-Memory Alloys With Extremely Small Hysteresis Width, Jun Cui, Yong Chu, Olugbenga Famodu, Yasubumi Furuya, Jason Hattrick-Simpers, Richard James, Alfred Ludwig, Sigurd Thienhaus, Manfred Wuttig, Zhiyong Zhang, Ichiro Takeuchi

Jason R. Hattrick-Simpers

No abstract provided.

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Tunable Multiferroic Properties In Nanocomposite Pbtio3-Cofe2O4 Epitaxial Thin Films, M. Murakami, K.-S. Chang, M. Aronova, C.-L. Lin, Ming Yu, Jason Hattrick-Simpers, M. Wuttig, I. Takeuchi, C. Gao, B. Hu, S. Lofland, L. Knauss, L. Bendersky Mar 2015

Tunable Multiferroic Properties In Nanocomposite Pbtio3-Cofe2O4 Epitaxial Thin Films, M. Murakami, K.-S. Chang, M. Aronova, C.-L. Lin, Ming Yu, Jason Hattrick-Simpers, M. Wuttig, I. Takeuchi, C. Gao, B. Hu, S. Lofland, L. Knauss, L. Bendersky

Jason R. Hattrick-Simpers

We report on the synthesis of PbTiO3–CoFe2O4 multiferroic nanocomposites and continuous tuning of their ferroelectric and magnetic properties as a function of the average composition on thin-film composition spreads. The highest dielectric constant and nonlinear dielectric signal was observed at (PbTiO3)85–(CoFe2O4)15, where robust magnetism was also observed. Transmission electron microscopy revealed a pancake-shaped epitaxial nanostructure of PbTiO3 on the order of 30 nm embedded in the matrix of CoFe2O4 at this composition. Composition dependent ferroics properties observed here indicate that there is considerable interdiffusion of cations into each other.

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Effects Of Neutron And Gamma Radiation On Lithium-Ion Batteries, Jie Qiu, Dandan He, Mingzhai Sun, Shimeng Li, Cun Wen, Jason Hattrick-Simpers, Yuan Zheng, Lei Cao Mar 2015

Effects Of Neutron And Gamma Radiation On Lithium-Ion Batteries, Jie Qiu, Dandan He, Mingzhai Sun, Shimeng Li, Cun Wen, Jason Hattrick-Simpers, Yuan Zheng, Lei Cao

Jason R. Hattrick-Simpers

No abstract provided.

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Multimode Quantitative Scanning Microwave Microscopy Of In Situ Grown Epitaxial Ba1-XSrXTio3 Composition Spreads, K. Chang, M. Aronova, O. Famodu, I. Takeuchi, S. Lofland, Jason Hattrick-Simpers, H. Chang Mar 2015

Multimode Quantitative Scanning Microwave Microscopy Of In Situ Grown Epitaxial Ba1-XSrXTio3 Composition Spreads, K. Chang, M. Aronova, O. Famodu, I. Takeuchi, S. Lofland, Jason Hattrick-Simpers, H. Chang

Jason R. Hattrick-Simpers

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.

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Reverse Stress Metastability Of Shunt Current In Cigs Solar Cells, Sourabh Dongaonkar, Erik Sheets, Rakesh Agrawal, Muhammad Alam Mar 2013

Reverse Stress Metastability Of Shunt Current In Cigs Solar Cells, Sourabh Dongaonkar, Erik Sheets, Rakesh Agrawal, Muhammad Alam

Sourabh Dongaonkar

Partial shading in thin film solar panels can result in reverse bias stress across shaded cells. Therefore, it is important to understand the effect of such reverse stress in commercially competitive PV technologies such as CIGS. In this paper, we systematically investigate the effect of moderate reverse bias on solution-processed CIGS solar cells. We subject the solar cells to varying degrees of reverse biases and continuously monitor the impact of the stress on dark current. We also explore the relaxation behavior of dark current following passive storage and the long term effect of the shadow stress on power output of …

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Performance Investigation Of A Hybrid Renewable Power Generation And Storage System Using Systemic Power Management Models, Damianos Giaouris, Athanasios Papadopoulos, Chrysa Ziogou, Dimiptris Ipsakis, Spyors Voutetakis, Simira Papadopoulou, Panos Seferlis, Fotis Stergiopoulos, Costas Elmasides Dec 2012

Performance Investigation Of A Hybrid Renewable Power Generation And Storage System Using Systemic Power Management Models, Damianos Giaouris, Athanasios Papadopoulos, Chrysa Ziogou, Dimiptris Ipsakis, Spyors Voutetakis, Simira Papadopoulou, Panos Seferlis, Fotis Stergiopoulos, Costas Elmasides

Sakis Papadopoulos

Hybrid renewable power generation systems considering storage of energy and/or hydrogen involve considerable complexity as heterogeneous equipment need to be interconnected and activated or deactivated at different time instances. This work employs generic and flexible decision making models to develop complex power/hydrogen management strategies and investigate their performance on systems integrating multiple power generation and storage devices. These models significantly facilitate the analysis of both a standalone power generation and storage system forming a microgrid currently in operation as well as three interconnected microgrids of different functionalities considered in this work. These systems are used to investigate the performance of …

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Spin-Spray Deposited Multiferroic Composite Ni₀.₂₃Fe₂.₇₇O₄/Pb(Zr,Ti)O₃ With Strong Interface Adhesion, Ming Liu, Ogheneyunume Obi, Jing Lou, Stephen Stoute, Jian Huang, Zhuhua Cai, Katherine Ziemer, Nian Sun Apr 2012

Spin-Spray Deposited Multiferroic Composite Ni₀.₂₃Fe₂.₇₇O₄/Pb(Zr,Ti)O₃ With Strong Interface Adhesion, Ming Liu, Ogheneyunume Obi, Jing Lou, Stephen Stoute, Jian Huang, Zhuhua Cai, Katherine Ziemer, Nian Sun

Jing Lou

Ni₀.₂₃Fe₂.₇₇O₄ (NFO)/Pb(Zr,Ti)O₃ (PZT) multiferroic composites were synthesized by spin-spray deposition of NFO film onto PZT at 90°C. Strong interface adhesion between NFO and PZT was observed, which was verified by high resolution transmission electron microscopy indicating excellent wetting between the NFO and PZT, and by the strong magnetoelectric coupling in the NFO/PZT multiferroic composite showing an electric field induced remnant magnetization change of 10%. This strong interface adhesion and low-temperature spin-spray synthesis of multiferroic materials provide an alternative route for novel integrated multiferroic materials and devices.

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Electrical Tuning Of Magnetism In Fe₃O₄/Pzn–Pt Multiferroic Heterostructures Derived By Reactive Magnetron Sputtering, Ming Liu, Ogheneyunume Obi, Zhuhua Cai, Jing Lou, Guomin Yang, Katherine Ziemer, Nian Sun Apr 2012

Electrical Tuning Of Magnetism In Fe₃O₄/Pzn–Pt Multiferroic Heterostructures Derived By Reactive Magnetron Sputtering, Ming Liu, Ogheneyunume Obi, Zhuhua Cai, Jing Lou, Guomin Yang, Katherine Ziemer, Nian Sun

Jing Lou

Strong magnetoelectric (ME) coupling was demonstrated in Fe₃O₄/PZN–PT (lead zinc niobate–lead titanate) multiferroic heterostructures obtained through a sputter deposition process. The dependence of the magnetic anisotropy on the electric field (E-field) is theoretically predicted and experimentally observed by ferromagnetic resonance spectroscopy. A large tunable in-plane magnetic anisotropy of up to 600 Oe, and tunable out-of-plane anisotropy of up to 400 Oe were observed in the Fe₃O₄/PZN–PT multiferroic heterostructures, corresponding to a large ME coefficient of 100 Oe cm/kV in plane and 68 Oe cm/kV out of plane, which match well with predicted results. In addition, the electric field manipulation of …

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Electrical Tuning Of Magnetism In Fe₃O₄/Pzn–Pt Multiferroic Heterostructures Derived By Reactive Magnetron Sputtering, Ming Liu, Ogheneyunume Obi, Zhuhua Cai, Jing Lou, Guomin Yang, Katherine Ziemer, Nian Sun Apr 2012

Electrical Tuning Of Magnetism In Fe₃O₄/Pzn–Pt Multiferroic Heterostructures Derived By Reactive Magnetron Sputtering, Ming Liu, Ogheneyunume Obi, Zhuhua Cai, Jing Lou, Guomin Yang, Katherine Ziemer, Nian Sun

Nian X. Sun

Strong magnetoelectric (ME) coupling was demonstrated in Fe₃O₄/PZN–PT (lead zinc niobate–lead titanate) multiferroic heterostructures obtained through a sputter deposition process. The dependence of the magnetic anisotropy on the electric field (E-field) is theoretically predicted and experimentally observed by ferromagnetic resonance spectroscopy. A large tunable in-plane magnetic anisotropy of up to 600 Oe, and tunable out-of-plane anisotropy of up to 400 Oe were observed in the Fe₃O₄/PZN–PT multiferroic heterostructures, corresponding to a large ME coefficient of 100 Oe cm/kV in plane and 68 Oe cm/kV out of plane, which match well with predicted results. In addition, the electric field manipulation of …

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Ba-Hexaferrite Films For Next Generation Microwave Devices, Vincent Harris (1962-), Zhaohui Chen, Yajie Chen, Soack Yoon, Tomokuza Sakai, Anton Geiler, Aria Yang, Yongxue He, Katherine Ziemer, Nian Sun, C. Vittoria Apr 2012

Ba-Hexaferrite Films For Next Generation Microwave Devices, Vincent Harris (1962-), Zhaohui Chen, Yajie Chen, Soack Yoon, Tomokuza Sakai, Anton Geiler, Aria Yang, Yongxue He, Katherine Ziemer, Nian Sun, C. Vittoria

Nian X. Sun

Next generation magnetic microwave devices require ferrite films to be thick (>300 μm), self-biased (high remanent magnetization), and low loss in the microwave and millimeter wave bands. Here we examine recent advances in the processing of thick Ba-hexaferrite (M-type) films using pulsed laser deposition (PLD), liquid-phase epitaxy, and screen printing. These techniques are compared and contrasted as to their suitability for microwave materials processing and industrial production. Recent advances include the PLD growth of BaM on wide-band-gap semiconductor substrates and the development of thick, self-biased, low-loss BaM films by screen printing.

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Correlation Between Texture, Anisotropy, And Vector Magnetization Processes Investigated By Two-Dimensional Vector Vibrating Sample Magnetometry In Bao(Fe₂O₃)₆ Thin Film, Paul Ohodnicki, K. Goh, Michael Mchenry, Katherine Ziemer, Zhaohui Chen, C. Vittoria, Vincent Harris (1962-) Apr 2011

Correlation Between Texture, Anisotropy, And Vector Magnetization Processes Investigated By Two-Dimensional Vector Vibrating Sample Magnetometry In Bao(Fe₂O₃)₆ Thin Film, Paul Ohodnicki, K. Goh, Michael Mchenry, Katherine Ziemer, Zhaohui Chen, C. Vittoria, Vincent Harris (1962-)

Vincent G. Harris

High ferromagnetic resonance frequencies and low linewidths in BaO(Fe₂O₃)₆ thin films are achieved by obtaining a low-dispersion of crystallite easy c axes normal to the film. X-ray diffraction and magnetic force microscopy are used to characterize texture and magnetic domain structure for a BaO(Fe₂O₃)₆ film deposited on (0001) SiC with a MgO (111) template layer. Strong c-axis texture normal to the film is observed resulting in strong uniaxial anisotropy. The consequent vector magnetization processes due to a combination of domain wall motion and magnetization rotation are characterized by two dimensional vector coil vibrating sample magnetometry (VVSM).

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Ba-Hexaferrite Films For Next Generation Microwave Devices, Vincent Harris (1962-), Zhaohui Chen, Yajie Chen, Soack Yoon, Tomokuza Sakai, Anton Geiler, Aria Yang, Yongxue He, Katherine Ziemer, Nian Sun, C. Vittoria Apr 2011

Ba-Hexaferrite Films For Next Generation Microwave Devices, Vincent Harris (1962-), Zhaohui Chen, Yajie Chen, Soack Yoon, Tomokuza Sakai, Anton Geiler, Aria Yang, Yongxue He, Katherine Ziemer, Nian Sun, C. Vittoria

Vincent G. Harris

Next generation magnetic microwave devices require ferrite films to be thick (>300 μm), self-biased (high remanent magnetization), and low loss in the microwave and millimeter wave bands. Here we examine recent advances in the processing of thick Ba-hexaferrite (M-type) films using pulsed laser deposition (PLD), liquid-phase epitaxy, and screen printing. These techniques are compared and contrasted as to their suitability for microwave materials processing and industrial production. Recent advances include the PLD growth of BaM on wide-band-gap semiconductor substrates and the development of thick, self-biased, low-loss BaM films by screen printing.

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