Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
-
- Multicolor quantum channel (3)
- Nanowire-based photonics (3)
- Polycrystalline tungsten nanotip (3)
- Two-color multiphoton photoemission (3)
- Ultrafast spin-polarized electrons (3)
-
- Particle tracking detectors (Solid-state detectors) (2)
- Radiation-hard detectors (2)
- Activity – stars (1)
- Atmospheres – planets and satellites (1)
- Charge transport (1)
- Debye temperature (1)
- Detector modelling and simulations II (electric fields (1)
- Distance verification (1)
- Electron emission (1)
- Erasure correction (1)
- Etc) (1)
- Gamma-Ray bursts (1)
- Individual (HD 189733 b) – stars (1)
- Individual (HD 189733) – techniques (1)
- Jahn–Teller distortions (1)
- LDPC codes (1)
- List decoding (1)
- Multiplication and induction (1)
- Planets and satellites (1)
- Pulse formation (1)
- Quantum stabilizer codes (1)
- Radio cherenkov (1)
- Solid state detectors (1)
- Spectroscopic (1)
- UHE Neutrinos (1)
Articles 1 - 29 of 29
Full-Text Articles in Entire DC Network
Phase Stability, Ordering Tendencies, And Magnetism In Single-Phase Fcc Au-Fe Nanoalloys, I. A. Zhuravlev, S. V. Barabash, J. M. An, K. D. Belashchenko
Phase Stability, Ordering Tendencies, And Magnetism In Single-Phase Fcc Au-Fe Nanoalloys, I. A. Zhuravlev, S. V. Barabash, J. M. An, K. D. Belashchenko
Department of Physics and Astronomy: Faculty Publications
Bulk Au-Fe alloys separate into Au-based fcc and Fe-based bcc phases, but L10 and L12 orderings were reported in single-phase Au-Fe nanoparticles. Motivated by these observations, we study the structural and ordering energetics in this alloy by combining density functional theory (DFT) calculations with effective Hamiltonian techniques: a cluster expansion with structural filters, and the configuration-dependent lattice deformation model. The phase separation tendency in Au-Fe persists even if the fcc-bcc decomposition is suppressed. The relative stability of disordered bcc and fcc phases observed in nanoparticles is reproduced, but the fully ordered L10 AuFe, L12 Au3Fe, and L12 AuFe3 structures are …
Distance Verification For Classical And Quantum Ldpc Codes, Ilya Dumer, Alexey Kovalev, Leonid P. Pryadko
Distance Verification For Classical And Quantum Ldpc Codes, Ilya Dumer, Alexey Kovalev, Leonid P. Pryadko
Department of Physics and Astronomy: Faculty Publications
The techniques of distance verification known for general linear codes are first applied to the quantum stabilizer codes. Then, these techniques are considered for classical and quantum (stabilizer) low-density-parity-check (LDPC) codes. New complexity bounds for distance verification with provable performance are derived using the average weight spectra of the ensembles of LDPC codes. These bounds are expressed in terms of the erasure-correcting capacity of the corresponding ensemble. We also present a new irreducible-cluster technique that can be applied to any LDPC code and takes advantage of parity-checks’ sparsity for both the classical and quantum LDPC codes. This technique reduces complexity …
Three-Dimensional Nanomagnetism, Amalio Fernández-Pacheco, Robert Streubel, Olivier Fruchart, Riccardo Hertel, Peter Fischer, Russell P. Cowburn
Three-Dimensional Nanomagnetism, Amalio Fernández-Pacheco, Robert Streubel, Olivier Fruchart, Riccardo Hertel, Peter Fischer, Russell P. Cowburn
Department of Physics and Astronomy: Faculty Publications
Magnetic nanostructures are being developed for use in many aspects of our daily life, spanning areas such as data storage, sensing and biomedicine. Whereas patterned nanomagnets are traditionally two-dimensional planar structures, recent work is expanding nanomagnetism into three dimensions; a move triggered by the advance of unconventional synthesis methods and the discovery of new magnetic effects. In three-dimensional nanomagnets more complex magnetic configurations become possible, many with unprecedented properties. Here we review the creation of these structures and their implications for the emergence of new physics, the development of instrumentation and computational methods, and exploitation in numerous applications.
Reversible Spin Texture In Ferroelectric Hfo2, L. L. Tao, Tula R. Paudel, Alexey Kovalev, Evgeny Tsymbal
Reversible Spin Texture In Ferroelectric Hfo2, L. L. Tao, Tula R. Paudel, Alexey Kovalev, Evgeny Tsymbal
Department of Physics and Astronomy: Faculty Publications
Spin-orbit coupling effects occurring in noncentrosymmetric materials are known to be responsible for nontrivial spin configurations and a number of emergent physical phenomena. Ferroelectric materials may be especially interesting in this regard due to reversible spontaneous polarization making possible a nonvolatile electrical control of the spin degrees of freedom. Here, we explore a technologically relevant oxide material, HfO2, which has been shown to exhibit robust ferroelectricity in a noncentrosymmetric orthorhombic phase. Using theoretical modelling based on density-functional theory, we investigate the spin-dependent electronic structure of the ferroelectric HfO2 and demonstrate the appearance of chiral spin textures driven by spin-orbit coupling. …
Pumping Of Magnons In A Dzyaloshinskii-Moriya Ferromagnet, Alexey Kovalev, Vladimir Zyuzin, Bo Li
Pumping Of Magnons In A Dzyaloshinskii-Moriya Ferromagnet, Alexey Kovalev, Vladimir Zyuzin, Bo Li
Department of Physics and Astronomy: Faculty Publications
We formulate a microscopic linear response theory of magnon pumping applicable to multiple-magnonic-band uniform ferromagnets with Dzyaloshinskii-Moriya interactions. From the linear response theory, we identify the extrinsic and intrinsic contributions where the latter is expressed via the Berry curvature of magnonic bands. We observe that in the presence of a time-dependent magnetization Dzyaloshinskii-Moriya interactions can act as fictitious electric fields acting on magnons. We study various current responses to this fictitious field and analyze the role of Berry curvature. In particular, we obtain an analog of the Hall-like response in systems with nontrivial Berry curvature of magnon bands. After identifying …
Two-Color Multiphoton Emission From Nanotips, Wayne Cheng-Wei Huang, Maria Becker, Joshua Beck, Herman Batelaan
Two-Color Multiphoton Emission From Nanotips, Wayne Cheng-Wei Huang, Maria Becker, Joshua Beck, Herman Batelaan
Department of Physics and Astronomy: Faculty Publications
Two-color multiphoton emission from polycrystalline tungsten nanotips has been demonstrated using two-color laser fields. The two-color photoemission is assisted by a three-photon multicolor quantum channel, which leads to a twofold increase in quantum efficiency. Weak-field control of two- color multiphoton emission was achieved by changing the efficiency of the quantum channel with pulse delay. The result of this study complements two-color tunneling photoemission in strong fields, and has potential applications for nanowire-based photonic devices. Moreover, the demonstrated two-color multiphoton emission may be important for realizing ultrafast spin-polarized electron sources via optically injected spin current.
Magnetically Ordered Transition-Metal-Intercalated Wse2, Pankaj Kumar, Ralph Skomski, Raghani Pushpa
Magnetically Ordered Transition-Metal-Intercalated Wse2, Pankaj Kumar, Ralph Skomski, Raghani Pushpa
Department of Physics and Astronomy: Faculty Publications
Introducing magnetic behavior in nonmagnetic transition metal dichalcogenides is essential to broaden their applications in spintronic and nanomagnetic devices. In this article, we investigate the electronic and magnetic properties of transition-metal-intercalated tungsten diselenide (WSe2) using density functional theory. We find that intercalation compounds with composition of T1/4WSe2 (T is an ironseries transition-metal atom) exhibit substantial magnetic moments and pronounced ferromagnetic order for late transition metals. The densities of states of the T atoms and the magnetic moments on the W sites indicate that the moments of the intercalated atoms become more localized with increasing atomic …
Two-Color Multiphoton Emission From Nanotips, Wayne Cheng Wei Huang, Maria Becker, Joshua Beck, Herman Batelaan
Two-Color Multiphoton Emission From Nanotips, Wayne Cheng Wei Huang, Maria Becker, Joshua Beck, Herman Batelaan
Department of Physics and Astronomy: Faculty Publications
Two-color multiphoton emission from polycrystalline tungsten nanotips has been demonstrated using two-color laser fields. The two-color photoemission is assisted by a three-photon multicolor quantum channel, which leads to a twofold increase in quantum efficiency. Weak-field control of twocolor multiphoton emission was achieved by changing the efficiency of the quantum channel with pulse delay. The result of this study complements two-color tunneling photoemission in strong fields, and has potential applications for nanowire-based photonic devices. Moreover, the demonstrated two-color multiphoton emission may be important for realizing ultrafast spin-polarized electron sources via optically injected spin current.
A Decade Of Hα Transits For Hd 189733 B: Stellar Activity Versus Absorption In The Extended Atmosphere, P. Wilson Cauley, Seth Redfield, Adam G. Jensen
A Decade Of Hα Transits For Hd 189733 B: Stellar Activity Versus Absorption In The Extended Atmosphere, P. Wilson Cauley, Seth Redfield, Adam G. Jensen
Department of Physics and Astronomy: Faculty Publications
HD 189733 b is one of the most well studied exoplanets due to its large transit depth and host star brightness. The focus on this object has produced a number of high-cadence transit observations using high-resolution optical spectrographs. Here we present an analysis of seven full Hα transits of HD 189733 b using HARPS on the 3.6 meter La Silla telescope and HIRES on Keck I, taken over the course of nine years from 2006 to 2015. Hα transmission signals are analyzed as a function of the stellar activity level, as measured using the normalized core flux of the Ca …
Superdomain Dynamics In Ferroelectric-Ferroelastic Films: Switching, Jamming, And Relaxation, J. F. Scott, A. Hershkovitz, Y. Ivry, H. Lu, A. Gruverman, J. M. Gregg
Superdomain Dynamics In Ferroelectric-Ferroelastic Films: Switching, Jamming, And Relaxation, J. F. Scott, A. Hershkovitz, Y. Ivry, H. Lu, A. Gruverman, J. M. Gregg
Department of Physics and Astronomy: Faculty Publications
Recent experimental work shows that ferroelectric switching can occur in large jumps in which ferroelastic superdomains switch together, rather than having the numerous smaller ferroelectric domains switch within them. In this sense, the superdomains play a role analogous to that of Abrikosov vortices in thin superconducting films under the Kosterlitz-Thouless framework, which control the dynamics more than individual Cooper pairs within them do. Here, we examine the dynamics of ferroelastic superdomains in ferroelastic ferroelectrics and their role in switching devices such as memories. Jamming of ferroelectric domains in thin films has revealed an unexpected time dependence of t-1/4 at …
Two-Color Multiphoton Emission From Nanotips, Wayne Cheng Wei Huang, Maria Becker, Joshua Beck, Herman Batelaan
Two-Color Multiphoton Emission From Nanotips, Wayne Cheng Wei Huang, Maria Becker, Joshua Beck, Herman Batelaan
Department of Physics and Astronomy: Faculty Publications
Two-color multiphoton emission from polycrystalline tungsten nanotips has been demonstrated using two-color laser fields. The two-color photoemission is assisted by a three-photon multicolor quantum channel, which leads to a twofold increase in quantum efficiency. Weak-field control of twocolor multiphoton emission was achieved by changing the efficiency of the quantum channel with pulse delay. The result of this study complements two-color tunneling photoemission in strong fields, and has potential applications for nanowire-based photonic devices. Moreover, the demonstrated two-color multiphoton emission may be important for realizing ultrafast spin-polarized electron sources via optically injected spin current.
Http As A Data Access Protocol: Trials With Xrootd In Cms’S Aaa Project, J. Balcas, B. P. Bockelman, D. Kcira, H. Newman, J. Vlimant, T. W. Hendricks
Http As A Data Access Protocol: Trials With Xrootd In Cms’S Aaa Project, J. Balcas, B. P. Bockelman, D. Kcira, H. Newman, J. Vlimant, T. W. Hendricks
Department of Physics and Astronomy: Faculty Publications
The main goal of the project to demonstrate the ability of using HTTP data federations in a manner analogous to the existing AAA infrastructure of the CMS experiment. An initial testbed at Caltech has been built and changes in the CMS software (CMSSW) are being implemented in order to improve HTTP support. The testbed consists of a set of machines at the Caltech Tier2 that improve the support infrastructure for data federations at CMS. As a first step, we are building systems that produce and ingest network data transfers up to 80 Gbps. In collaboration with AAA, HTTP support is …
Exploring Compression Techniques For Root Io, Z. Zhang, B. Bockelman
Exploring Compression Techniques For Root Io, Z. Zhang, B. Bockelman
Department of Physics and Astronomy: Faculty Publications
ROOT provides an flexible format used throughout the HEP community. The number of use cases - from an archival data format to end-stage analysis - has required a number of tradeoffs to be exposed to the user. For example, a high “compression level” in the traditional DEFLATE algorithm will result in a smaller file (saving disk space) at the cost of slower decompression (costing CPU time when read). At the scale of the LHC experiment, poor design choices can result in terabytes of wasted space or wasted CPU time. We explore and attempt to quantify some of these tradeoffs. Specifically, …
Effects Of Biaxial Strain On The Improper Multiferroicity In H-Lufeo3 Films Studied Using The Restrained Thermal Expansion Method, Kishan Sinha, Yubo Zhang, Xuanyuan Jiang, Hongwei Wang, Xiao Wang, Xiaozhe Zhang, Philip J. Ryan, Jong-Woo Kim, John Bowlan, Dmitry A. Yarotski, Yuelin Li, Anthony D. Dichiara, Xuemei Cheng, Xifan Wu, Xiaoshan Xu
Effects Of Biaxial Strain On The Improper Multiferroicity In H-Lufeo3 Films Studied Using The Restrained Thermal Expansion Method, Kishan Sinha, Yubo Zhang, Xuanyuan Jiang, Hongwei Wang, Xiao Wang, Xiaozhe Zhang, Philip J. Ryan, Jong-Woo Kim, John Bowlan, Dmitry A. Yarotski, Yuelin Li, Anthony D. Dichiara, Xuemei Cheng, Xifan Wu, Xiaoshan Xu
Department of Physics and Astronomy: Faculty Publications
Elastic strain is potentially an important approach in tuning the properties of the improperly multiferroic hexagonal ferrites, the details of which, however, have been elusive due to experimental difficulties. Employing the method of restrained thermal expansion, we have studied the effect of isothermal biaxial strain in the basal plane of h-LuFeO3 (001) films. The results indicate that a compressive biaxial strain significantly enhances the K3 structural distortion (the order parameter of the improper ferroelectricity), and the effect is larger at higher temperatures. The compressive biaxial strain and the enhanced K3 structural distortion together cause an increase …
Constraints On The Ultra-High-Energy Neutrino Flux From Gamma-Ray Bursts From A Prototype Station Of The Askaryan Radio Array, P. Allison, J. Auffenberg, R. Bard, J. J. Beatty, D. Z. Besson, C. Bora, C.-C. Chen, P. Chen, A. Connolly, J. P. Davies, M. A. Duvernois, B. Fox, P. W. Gorham, K. Hanson, B. Hill, K. D. Hoffman, E. Hong, L.-C. Hu, A. Ishihara, A. Karle, J. Kelley, Ilya Kravchenko, H. Landsman, A. Laundrie, C.-J. Li, T. Liu, M.-Y. Lu, R. Maunu, K. Mase, T. Meures, C. Miki, J. Nam, R. J. Nichol, G. Nir, A. Ó Murchadha, C. G. Pfendner, Kenneth L. Ratzlaff, B. Rotter, P. Sandstrom, D. Seckel, A. Shultz, M. Song, J. Stockham, M. Stockham, M. Sullivan, J. Touart, H.-Y. Tu, G. S. Varner, S. Yoshida, R. Young, M. Bustamante, D. Guetta
Constraints On The Ultra-High-Energy Neutrino Flux From Gamma-Ray Bursts From A Prototype Station Of The Askaryan Radio Array, P. Allison, J. Auffenberg, R. Bard, J. J. Beatty, D. Z. Besson, C. Bora, C.-C. Chen, P. Chen, A. Connolly, J. P. Davies, M. A. Duvernois, B. Fox, P. W. Gorham, K. Hanson, B. Hill, K. D. Hoffman, E. Hong, L.-C. Hu, A. Ishihara, A. Karle, J. Kelley, Ilya Kravchenko, H. Landsman, A. Laundrie, C.-J. Li, T. Liu, M.-Y. Lu, R. Maunu, K. Mase, T. Meures, C. Miki, J. Nam, R. J. Nichol, G. Nir, A. Ó Murchadha, C. G. Pfendner, Kenneth L. Ratzlaff, B. Rotter, P. Sandstrom, D. Seckel, A. Shultz, M. Song, J. Stockham, M. Stockham, M. Sullivan, J. Touart, H.-Y. Tu, G. S. Varner, S. Yoshida, R. Young, M. Bustamante, D. Guetta
Department of Physics and Astronomy: Faculty Publications
We report on a search for ultra-high-energy (UHE) neutrinos from gamma-ray bursts (GRBs) in the data set collected by the Testbed station of the Askaryan Radio Array (ARA) in 2011 and 2012. From 57 selected GRBs, we observed no events that survive our cuts, which is consistent with 0.12 expected background events. Using NeuCosmA as a numerical GRB reference emission model, we estimate upper limits on the prompt UHE GRB neutrino fluence and quasi-diffuse flux from 107 to 1010 GeV. This is the first limit on the prompt UHE GRB neutrino quasi-diffuse flux above 107 GeV.
Enhanced Superconductivity In Tio Epitaxial Thin Films, Chao Zhang, Feixiang Hao, Guanyin Gao, Xiang Liu, Chao Ma, Yue Lin, Yuewei Yin, Xiaoguang Li
Enhanced Superconductivity In Tio Epitaxial Thin Films, Chao Zhang, Feixiang Hao, Guanyin Gao, Xiang Liu, Chao Ma, Yue Lin, Yuewei Yin, Xiaoguang Li
Department of Physics and Astronomy: Faculty Publications
Titanium oxides have many fascinating optical and electrical properties, such as the superconductivity at 2 K in cubic titanium monoxide (TiO) polycrystalline bulk. However, the lack of TiO single crystals or epitaxial films has prevented systematic investigations on its superconductivity. Here, we report the basic superconductivity characterizations of cubic TiO films epitaxially grown on (0001)-oriented α-Al2O3 substrates. The magnetic and electronic transport measurements confirmed that TiO is a type-II superconductor and the recorded high Tc is about 7.4 K. The lower critical field (Hc1) at 1.9 K, the extrapolated upper critical field Hc2(0), and coherence length …
Tunable Dimensional Crossover And Magnetocrystalline Anisotropy In Fe2p-Based Alloys, I. A. Zhuravlev, V. P. Antropov, A. Vishina, M. Van Schilfgaarde, Kirill D. Belashchenko
Tunable Dimensional Crossover And Magnetocrystalline Anisotropy In Fe2p-Based Alloys, I. A. Zhuravlev, V. P. Antropov, A. Vishina, M. Van Schilfgaarde, Kirill D. Belashchenko
Department of Physics and Astronomy: Faculty Publications
Electronic structure calculations are used to examine the magnetic properties of Fe2P-based alloys and the mechanisms through which the Curie temperature andmagnetocrystalline anisotropy can be optimized for specific applications. It is found that at elevated temperatures the magnetic interaction in pure Fe2P develops a pronounced two-dimensional character due to the suppression of the magnetization in one of the sublattices, but the interlayer coupling is very sensitive to band filling and structural distortions. This feature suggests a natural explanation for the observed sharp enhancement of the Curie temperature by alloying with multiple elements, such as Co, Ni, …
Nonadiabatic Berry Phase In Nanocrystalline Magnets, R. Skomski, David J. Sellmyer
Nonadiabatic Berry Phase In Nanocrystalline Magnets, R. Skomski, David J. Sellmyer
Department of Physics and Astronomy: Faculty Publications
It is investigated how a Berry phase is created in polycrystalline nanomagnets and how the phase translates into an emergent magnetic field and into a topological Hall-effect contribution. The analysis starts directly from the spin of the conduction electrons and does not involve any adiabatic Hamiltonian. Completely random spin alignment in the nanocrystallites does not lead to a nonzero emergent field, but a modulation of the local magnetization does. As an explicit example, we consider a wire with a modulated cone angle.
Intense-Field Photoionization Of Molecules Using Ultrashort Radiation Pulses: Rempi In Toluene, Aniline, Phenol, And Fluorobenzene, Joshua Beck, Collin J. Mcacy, Timothy Scarborough, Cornelis J. Uiterwaal
Intense-Field Photoionization Of Molecules Using Ultrashort Radiation Pulses: Rempi In Toluene, Aniline, Phenol, And Fluorobenzene, Joshua Beck, Collin J. Mcacy, Timothy Scarborough, Cornelis J. Uiterwaal
Department of Physics and Astronomy: Faculty Publications
We investigate the intense-field photodynamics of molecules using 50-fs pulses with intensities of 1012 to 1014 W/cm2 at 800-nm from a Ti:sapphire laser. We use a mass spectrometer that avoids focal intensity averaging. We have investigated the isoelectronic target molecules toluene (C6H5-CH3), aniline (C6H5-NH2), phenol (C6H5-OH), and fluorobenzene (C6H5-F). We discuss a resonance-enhanced multiphoton ionization (REMPI) mechanism that includes the AC Stark shifts of the molecular states. We have also investigated CO2 and CS2. For these …
Cms Connect, J. Balcas, B. Bockelman, R. Gardner Jr., K. Hurtado Anampa, B. Jayatilaka, F. Aftab Khan, K. Lannon, K. Larson, J. Letts, J. Marra Da Silva, M. Mascheroni, D. Mason, A. Perez-Calero Yzquierdo, A. Tiradani
Cms Connect, J. Balcas, B. Bockelman, R. Gardner Jr., K. Hurtado Anampa, B. Jayatilaka, F. Aftab Khan, K. Lannon, K. Larson, J. Letts, J. Marra Da Silva, M. Mascheroni, D. Mason, A. Perez-Calero Yzquierdo, A. Tiradani
Department of Physics and Astronomy: Faculty Publications
The CMS experiment collects and analyzes large amounts of data coming from high energy particle collisions produced by the Large Hadron Collider (LHC) at CERN. This involves a huge amount of real and simulated data processing that needs to be handled in batch-oriented platforms. The CMS Global Pool of computing resources provide +100K dedicated CPU cores and another 50K to 100K CPU cores from opportunistic resources for these kind of tasks and even though production and event processing analysis workflows are already managed by existing tools, there is still a lack of support to submit final stage condor-like analysis jobs …
Magnetocrystalline Anisotropy Of #-Fe2o3, Imran Ahamed, Rohit Pathak, Ralph Skomski, Arti Kashyap
Magnetocrystalline Anisotropy Of #-Fe2o3, Imran Ahamed, Rohit Pathak, Ralph Skomski, Arti Kashyap
Department of Physics and Astronomy: Faculty Publications
The epsilon Fe2O3 phase of iron oxide has been studied to understand the spin structure and the magnetocrystalline anisotropy in the bulk and in thin films of ε-Fe2O3 and Co-doped ε-Fe2O3. The preferential magnetization direction in the nanoparticles of ε-Fe2O3 is along the a-axis [M. Gich et al., Chem. Mater. 18, 3889 (2006)]. Compared to the bulk band gap of 1.9 eV, the thin-film band gap is reduced to 1.3 eV in the Co-free films and to 0.7 eV in the film with partial Co substitution. The …
First-Principle Investigation Of Structural, Electronic And Magnetic Properties Of Co2vin And Covin Heusler Compounds, Muthui Zipporah, Pathak Rohit, Musembi Robinson, Mwabora Julius, Skomski Ralph, Kashyap Arti
First-Principle Investigation Of Structural, Electronic And Magnetic Properties Of Co2vin And Covin Heusler Compounds, Muthui Zipporah, Pathak Rohit, Musembi Robinson, Mwabora Julius, Skomski Ralph, Kashyap Arti
Department of Physics and Astronomy: Faculty Publications
Investigation of the structural, electronic and magnetic properties of full-Heusler Co2VIn as well as half-Heusler CoVIn Cobalt based Heusler compounds using density functional theory (DFT) leads to the general conclusion that Co2VIn and CoVIn are half-metallic materials with a gap at the Fermi level in the minority states and majority states respectively. A Hubbard-like Coulomb correlation term U has been included in the DFT (DFT+U) for the computation of the electronic and magnetic properties of the compounds. The structural properties have been calculated for the paramagnetic and ferromagnetic phases, and both Co2VIn …
The Lattice Stiffening Transition In Uo2 Single Crystals, Christopher Young, James Petrosky, J. Matthew Mann, Eric M. Hunt, David Turner, Peter A. Dowben
The Lattice Stiffening Transition In Uo2 Single Crystals, Christopher Young, James Petrosky, J. Matthew Mann, Eric M. Hunt, David Turner, Peter A. Dowben
Department of Physics and Astronomy: Faculty Publications
The effective Debye temperatures (θDE) of the surface region of UO2 single crystals, prepared by the hydrothermal synthesis technique, were obtained from temperature-dependent x-ray photoemission in the temperature range of 300 K–623 K. A lattice stiffening transition, characterized by different regions of different effective Debye temperature, 500 ± 59 K below 475 K and 165 ± 21 K above 475 K is identified. A comparison of the temperature dependence of the effective UO2 Debye temperature, with the changes in the lattice expansion coefficient for UO2, support strong lattice-phonon interaction arising from the Jahn–Teller distortion.
Accessing Data Federations With Cvmfs, Derek Weitzel, Brian Bockelman, Dave Dykstra, Jakob Blomer, Ren Meusel
Accessing Data Federations With Cvmfs, Derek Weitzel, Brian Bockelman, Dave Dykstra, Jakob Blomer, Ren Meusel
Department of Physics and Astronomy: Faculty Publications
Data federations have become an increasingly common tool for large collaborations such as CMS and Atlas to efficiently distribute large data files. Unfortunately, these typically are implemented with weak namespace semantics and a non-POSIX API. On the other hand, CVMFS has provided a POSIX-compliant read-only interface for use cases with a small working set size (such as software distribution). The metadata required for the CVMFS POSIX interface is distributed through a caching hierarchy, allowing it to scale to the level of about a hundred thousand hosts. In this paper, we will describe our contributions to CVMFS that merges the data …
Structure Evolution And Multiferroic Properties In Cobalt Doped Bi4Ndti3Fe1-XCoXO15- Bi3Ndti2Fe1-XCoxo12-Δ Intergrowth Aurivillius Compounds, D. L. Zhang, W. C. Huang, Z. W. Chen, W. B. Zhao, L. Feng, M. Li, Y. W. Yin, S. N. Dong, X. G. Li
Structure Evolution And Multiferroic Properties In Cobalt Doped Bi4Ndti3Fe1-XCoXO15- Bi3Ndti2Fe1-XCoxo12-Δ Intergrowth Aurivillius Compounds, D. L. Zhang, W. C. Huang, Z. W. Chen, W. B. Zhao, L. Feng, M. Li, Y. W. Yin, S. N. Dong, X. G. Li
Department of Physics and Astronomy: Faculty Publications
Here, we report the structure evolution, magnetic and ferroelectric properties in Co-doped 4- and 3-layered intergrowth Aurivillius compounds Bi4NdTi3Fe1-x CoxO15-Bi3NdTi2Fe1-xCoxO12-δ. The compounds suffer a structure evolution from the parent 4-layered phase (Bi4NdTi3FeO15) to 3-layered phase (Bi3NdTi2CoO12-δ) with increasing cobalt doping level from 0 to 1. Meanwhile the remanent magnetization and polarization show opposite variation tendencies against the doping level, and the sample with x = …
P-Type Silicon Strip Sensors For The New Cms Tracker At Hl-Lhc, Alexander Dierlamm, K. Bloom, D. R. Claes, C. Fangmeier, R. Gonzalez Suarez, J. Monroy, J. Siado
P-Type Silicon Strip Sensors For The New Cms Tracker At Hl-Lhc, Alexander Dierlamm, K. Bloom, D. R. Claes, C. Fangmeier, R. Gonzalez Suarez, J. Monroy, J. Siado
Department of Physics and Astronomy: Faculty Publications
The upgrade of the LHC to the High-Luminosity LHC (HL-LHC) is expected to increase the LHC design luminosity by an order of magnitude. This will require silicon tracking detectors with a significantly higher radiation hardness. The CMS Tracker Collaboration has conducted an irradiation and measurement campaign to identify suitable silicon sensor materials and strip designs for the future outer tracker at the CMS experiment. Based on these results, the collaboration has chosen to use n-in-p type silicon sensors and focus further investigations on the optimization of that sensor type. This paper describes the main measurement results and conclusions that motivated …
Dualism Between Optical And Difference Parametric Amplification, Wayne Cheng-Wei Huang, Herman Batelaan
Dualism Between Optical And Difference Parametric Amplification, Wayne Cheng-Wei Huang, Herman Batelaan
Department of Physics and Astronomy: Faculty Publications
Breaking the symmetry in a coupled wave system can result in unusual amplification behavior. In the case of difference parametric amplification the resonant pump frequency is equal to the difference, instead of the sum, frequency of the normal modes. We show that sign reversal in the symmetry relation of parametric coupling give rise to difference parametric amplification as a dual of optical parametric amplification. For optical systems, our result can potentially be used for efficient XUV amplification.
Controlling The Microstructure And Associated Magnetic Properties Of Ni0.2mn3.2ga0.6 Melt-Spun Ribbons By Annealing, Mahmud Khan, Ohud Alshammari, Balamurugan Balamurugan, Bhaskar Das, David J. Sellmyer, Ahmad Us Saleheen, Shane Stadler
Controlling The Microstructure And Associated Magnetic Properties Of Ni0.2mn3.2ga0.6 Melt-Spun Ribbons By Annealing, Mahmud Khan, Ohud Alshammari, Balamurugan Balamurugan, Bhaskar Das, David J. Sellmyer, Ahmad Us Saleheen, Shane Stadler
Department of Physics and Astronomy: Faculty Publications
Here we report on the structural and magnetic properties of Ni0.2Mn3.2Ga0.6 meltspun ribbons. The as-spun ribbons were found to exhibit mixed cubic phases that transform to non-cubic structure upon annealing. Additionally, an amorphous phase was found to co-exist in all ribbons. The SEM images show that minor grain formation occurs on the as-spun ribbons. However, the formation of extensive nano-grains was observed on the surfaces of the annealed ribbons. While the as-spun ribbons exhibit predominantly paramagnetic behavior, the ribbons annealed under various thermal conditions were found to be ferromagnetic with a Curie temperature of about …
Test Beam Performance Measurements For The Phase I Upgrade Of The Cms Pixel Detector, M. Dragicevic, Cms Collaboration
Test Beam Performance Measurements For The Phase I Upgrade Of The Cms Pixel Detector, M. Dragicevic, Cms Collaboration
Department of Physics and Astronomy: Faculty Publications
A new pixel detector for the CMS experiment was built in order to cope with the instantaneous luminosities anticipated for the Phase I Upgrade of the LHC. The new CMS pixel detector provides four-hit tracking with a reduced material budget as well as new cooling and powering schemes. A new front-end readout chip mitigates buffering and bandwidth limitations, and allows operation at low comparator thresholds. In this paper, comprehensive test beam studies are presented, which have been conducted to verify the design and to quantify the performance of the new detector assemblies in terms of tracking efficiency and spatial resolution. …