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Articles 1 - 13 of 13
Full-Text Articles in Physics
Data Management And Visualization Of X-Ray Diffraction Spectra From Thin Film Ternary Composition Spreads, I. Takeuchi, C. Long, O. Famodu, M. Murakami, Jason Hattrick-Simpers, G. Rubloff, M. Stukowski, K. Rajan
Data Management And Visualization Of X-Ray Diffraction Spectra From Thin Film Ternary Composition Spreads, I. Takeuchi, C. Long, O. Famodu, M. Murakami, Jason Hattrick-Simpers, G. Rubloff, M. Stukowski, K. Rajan
Jason R. Hattrick-Simpers
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 …
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
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 …
Rapid Structural Mapping Of Ternary Metallic Alloy Systems Using The Combinatorial Approach And Cluster Analysis, C. Long, Jason Hattrick-Simpers, M. Murakami, R. Srivastava, I. Takeuchi, V. Karen, X. Li
Rapid Structural Mapping Of Ternary Metallic Alloy Systems Using The Combinatorial Approach And Cluster Analysis, C. Long, Jason Hattrick-Simpers, M. Murakami, R. Srivastava, I. Takeuchi, V. Karen, X. Li
Jason R. Hattrick-Simpers
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, …
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
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 …
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
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.
Note: A Simple Thermal Gradient Annealing Unit For The Treatment Of Thin Films, C. Metting, Johnathan Bunn, Ellen Underwood, Yihao Zhu, G. Koley, T. Crawford, Jason Hattrick-Simpers
Note: A Simple Thermal Gradient Annealing Unit For The Treatment Of Thin Films, C. Metting, Johnathan Bunn, Ellen Underwood, Yihao Zhu, G. Koley, T. Crawford, Jason Hattrick-Simpers
Jason R. Hattrick-Simpers
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.
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
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.
Optical Cell For Combinatorial In Situ Raman Spectroscopic Measurements Of Hydrogen Storage Materials At High Pressures And Temperatures, Jason Hattrick-Simpers, Wilbur Hurst, Sesha Srinivasan, James Maslar
Optical Cell For Combinatorial In Situ Raman Spectroscopic Measurements Of Hydrogen Storage Materials At High Pressures And Temperatures, Jason Hattrick-Simpers, Wilbur Hurst, Sesha Srinivasan, James Maslar
Jason R. Hattrick-Simpers
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 …
An Infrared Imaging Method For High-Throughput Combinatorial Investigation Of Hydrogenation-Dehydrogenation And New Phase Formation Of Thin Films, H. Oguchi, Jason Hattrick-Simpers, I. Takeuchi, E. Heilweil, L. Bendersky
An Infrared Imaging Method For High-Throughput Combinatorial Investigation Of Hydrogenation-Dehydrogenation And New Phase Formation Of Thin Films, H. Oguchi, Jason Hattrick-Simpers, I. Takeuchi, E. Heilweil, L. Bendersky
Jason R. Hattrick-Simpers
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 Mg thin …
Effect Of Trans-Cis Photoisomerization On Phase Equilibria And Phase Transition Of Liquid-Crystalline Azobenzene Chromophore And Its Blends With Reactive Mesogenic Diacrylate, Namil Kim, Quan Li, Thein Kyu
Effect Of Trans-Cis Photoisomerization On Phase Equilibria And Phase Transition Of Liquid-Crystalline Azobenzene Chromophore And Its Blends With Reactive Mesogenic Diacrylate, Namil Kim, Quan Li, Thein Kyu
Thein Kyu
Photoisomerization-induced phase transition of neat liquid-crystalline azobenzene chromophore (LCAC) and its effect on phase diagrams of its mixtures with reactive mesogenic diacrylate monomer (RM257) have been investigated experimentally and theoretically. Upon irradiation with ultraviolet light, the nematic phase of LCAC transformed to isotropic, while the crystal phase showed corrugated textures on the surface (i.e., ripples). The phase-transition temperatures and corresponding morphologies of the blends have been investigated by means of differential scanning calorimetry and optical microscopy. A theoretical phase diagram of a binary nematic and crystalline system was constructed by self-consistently solving the combined free energies of Flory-Huggins, Maier-Saupe, and …
Spatio-Temporal Growth Of Nematic Domains In Liquid Crystal Polymer Mixtures, Hao-Wen Chiu, Thein Kyu
Spatio-Temporal Growth Of Nematic Domains In Liquid Crystal Polymer Mixtures, Hao-Wen Chiu, Thein Kyu
Thein Kyu
Dynamics of phase separation and morphology development in mixtures of a low molar mass liquid crystal (LC) and a polymer have been investigated theoretically in comparison with experimental results. In the theoretical model, the combined free-energy densities of Flory-Huggins theory for isotropic mixing and Maier-Saupe theory for nematic ordering have been incorporated into the time-dependent Ginzburg-Landau equation (type C). The temporal evolution of the structure factor and the emergence of phase-separated liquid crystal domains have been simulated on the basis of an explicit central difference method based on a square lattice (128 x 128) with a periodic boundary condition. Of …
Observation Of Novel Liquid-Crystalline Phase Above The Bulk-Melting Temperature, Keshav Gautam, Satyendra Kumar, Didier Wermeille, Doug Robinson, Ali Dhinojwala
Observation Of Novel Liquid-Crystalline Phase Above The Bulk-Melting Temperature, Keshav Gautam, Satyendra Kumar, Didier Wermeille, Doug Robinson, Ali Dhinojwala
Ali Dhinojwala
In this paper, we show that a noncrystalline but ordered smectic-like phase exists above the bulk-melting temperature (T-m) at poly(n-alkyl acrylates)-air interface. The surface ordered phase is one monolayer thick and undergoes a sharp transition from order to disorder 10degreesC above T-m for n=22. The presence of a surface phase that does not exist in the bulk has important implications in the design of thermally responsive adhesives.
Statistical Mechanics Of Wormlike Polymers From A New Generating Function. Ii. The Force-Elongation Relationship, Gustavo Carri
Statistical Mechanics Of Wormlike Polymers From A New Generating Function. Ii. The Force-Elongation Relationship, Gustavo Carri
Gustavo A. Carri
No abstract provided.