Other Physics Commons^™

Structure And Magnetism Of Mn5ge3 Nanoparticles, Onur Tosun, Mohammed Salehi-Fashami, Balamurugan Balasubramanian, Ralph Skomski, David J. Sellmyer, George C. Hadjipanayis

Nebraska Center for Materials and Nanoscience: Faculty Publications

In this work, we investigated the magnetic and structural properties of isolated Mn₅Ge₃ nanoparticles prepared by the cluster-beam deposition technique. Particles with sizes between 7.2 and 12.6 nm were produced by varying the argon pressure and power in the cluster gun. X-ray diffraction (XRD)and selected area diffraction (SAD) measurements show that the nanoparticles crystallize in the hexagonal Mn₅Si₃-type crystal structure, which is also the structure of bulk Mn₅Ge₃. The temperature dependence of the magnetization shows that the as-made particles are ferromagnetic at room temperature and have slightly different Curie …

Structural, Magnetic, And Electron-Transport Properties Of Epitaxial Mn2Ptsn Films, Y. Jin, Shah R. Valloppilly, Parashu Kharel, Jace Waybright, Pavel V. Lukashev, Xingzhong Li, David J. Sellmyer

Nebraska Center for Materials and Nanoscience: Faculty Publications

The growth of new magnetic materials on suitable insulating substrates is an important part of the development of spin-electronics devices for memory or information processing. Epitaxial thin films of Mn₂PtSn were grown on a MgO [001] substrate by magnetron co-sputtering of the constituents. Structural, magnetic, and electron-transport properties were investigated. The epitaxial Mn₂PtSn film has an inverse tetragonal structure with the c-axis aligned in the plane of the MgO substrate. The lattice constants determined using XRD and TEM analysis are c=6.124Å and a=b=4.505Å. The orientation of Mn₂PtSn c-axis which …

Applications Of Effective Field Theories To New Physics, Derek Edward Hazard

Wayne State University Dissertations

We apply an effective field theory approach and argue that lepton flavor violating (LFV) decays M → l1l2 of meson states M with different quantum numbers could be used to put constraints on the Wilson coefficients of effective operators describing LFV interactions at low energy scales. We note that the restricted kinematics of the two-body decay of quarkonium or a heavy quark meson allows us to select operators with particular quantum numbers, significantly reducing the reliance on the single operator dominance assumption that is prevalent in constraining parameters of the effective LFV Lagrangian. We shall also argue that studies of …

Towards A Strong Spin–Orbit Coupling Magnetoelectric Transistor, Peter Dowben, Christian Binek, Kai Zhang, Lu Wang, Wai-Ning Mei, Jonathan P. Bird, Uttam Singisetti, Xia Hong, Kang L. Wang, Dmitri Nikonov

Peter Dowben Publications

Here, we outline magnetoelectric (ME) device concepts based on the voltage control of the interface magnetism of an ME antiferromagnet gate dielectric formed on a very thin semiconductor channel with large spin–orbit coupling (SOC). The emphasis of the ME spin field-effect transistors (ME spin FET) is on an antiferromagnet spin–orbit read logic device and a ME spin-FET multiplexer. Both spin-FET schemes exploit the strong SOC in the semiconducting channel materials but remain dependent on the voltage-induced switching of an ME, so that the switching time is limited only by the switching dynamics of the ME. The induced exchange field spin …

Can A Comprehensive Transition Plan To Barefoot Running Be The Solution To The Injury Epidemic In American Endurance Runners?, Michael A. Scarlett

CMC Senior Theses

Fossils belonging to the genus Homo, dating as far back as two million years ago, exhibit uniquely efficient features suggesting that early humans had evolved to become exceptional endurance runners. Although they did not have the cushion or stability-control features provided in our modern day running shoes, our early human ancestors experienced far less of the running-related injuries we experience today. The injury rate has been estimated as high as 90% annually for Americans training for a marathon and as high as 79% annually for all American endurance runners. There is an injury epidemic in conventionally shod populations that …

Climate Modeling, Outgoing Longwave Radiation, And Tropical Cyclone Forecasting, Thomas Rechtman

Honors Undergraduate Theses

Climate modeling and tropical cyclone forecasting are two significant is- sues that are continuously being improved upon for more accurate weather forecasting and preparedness. In this thesis, we have studied three climate models and formulated a new model with a view to determine the outgoing longwave radiation (OLR) budget at the top of the atmosphere (TOA) as ob- served by the National Oceanic and Atmospheric Administration’s (NOAA) satellite based Advanced Very High Resolution Radiometer (AVHRR). In 2006, Karnauskas proposed the African meridional OLR as an Atlantic hur- ricane predictor, the relation was further proven in 2016 by Karnauskas and Li …

Kinetic Monte Carlo Simulation Of Binary Alloys, Timothy Craig Marshall

Theses and Dissertations

There are many tools to simulate physical phenomena. Generally, the simulation technique is defined by the size of the simulation area. Two well know techniques for simulating atom dynamics are kinetic Monte Carlo (kMC) and molecular dynamics (MD). In this work we simulate physical vapor deposition of binary metallic systems using the kMC technique. A sufficient quantity of atoms are deposited so that morphological features can be observed. Where kMC has fallen short we have used MD to supplement our results.

Spatial Patterns In Lightning Flashes Centered On Tornadoes, Alexander Ziemecki

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

The Inferential Design Of Entropy And Its Application To Quantum Measurements, Kevin Vanslette

Legacy Theses & Dissertations (2009 - 2024)

This thesis synthesizes probability and entropic inference with Quantum Mechanics and quantum measurement [1-6]. It is shown that the standard and quantum relative entropies are tools \emph{designed} for the purpose of updating probability distributions and density matrices, respectively [1]. The derivation of the standard and quantum relative entropy are completed in tandem following the same inferential principles and design criteria. This provides the first design derivation of the quantum relative entropy while also reducing the number of required design criteria to two.

The Entropic Dynamics Approach To The Paradigmatic Quantum Mechanical Phenomena, Susan Difranzo

Legacy Theses & Dissertations (2009 - 2024)

Standard Quantum Mechanics, although successful in terms of calculating and predicting

Black Hole Microstates & Integrable Deformation In String Theory, Jia Tian

Legacy Theses & Dissertations (2009 - 2024)

In this thesis, we study microstate geometries of black holes in string theory and explore several aspects of integrabile Conformal Field Theories (CFTs).

Warp Drive Spacetimes, Nicholas A.S. Driver

Theses and Dissertations

The concept of faster than light travel in general relativity is examined, starting with a review of the Alcubierre metric. This spacetime, although incredible in its implications, has certain unavoidable problems which are discussed in detail. It is demonstrated that in order to describe faster than light travel without any ambiguities, a coordinate independent description is much more convenient. An alternative method of describing superluminal travel is then proposed, which has similarities to the Krasnikov tube.

Evaporation Of A Sessile Droplet On A Slope, Mitch Timm

Dissertations, Master's Theses and Master's Reports

We theoretically examine the drying of a stationary liquid droplet on an inclined surface. Both analytical and numerical approaches are considered, while assuming that the evaporation results from a purely diffusive transport of the liquid vapor and that the contact line is a pinned circle. For the purposes of our analytical calculations, we suppose that the effect of gravity relative to the surface tension is weak, i.e. the Bond number (Bo) is small. Then, we express the shape of the drop and the vapor concentration field as perturbation expansions in terms of Bo. When the Bond number is zero, the …

Question 1: Iceberg To Los Angeles, Question 2: Lost Luggage, Larry Weinstein

Physics Faculty Publications

How much fuel would it take to tow a large enough iceberg to Los Angeles to provide fresh water for the city for an entire year? (Thanks to John Adam of Old Dominion University and co-author of Guesstimation for suggesting the question.)

U.S.-based airlines lost 1.7 million pieces of luggage in 2016. How tall a mountain will this make? What is the probability an airline will lose our luggage on our next flight? (Thanks to John Adam of Old Dominion University and co-author of Guesstimation for suggesting the question.)

Addressing The Proton Radius Puzzle Using Qed-Nrqed Effective Field Theory, Steven Patrick Dye

Wayne State University Dissertations

In 2010 the first extraction of the proton charge radius from muonic hydrogen was found to be five standard deviations away from the regular hydrogen value. Seven years later, this proton radius puzzle still persists, and challenges our understanding of the structure of the proton. An effective field theory analysis using Non-Relativistic Quantum Electrody- namics (NRQED) indicates that the muonic hydrogen result can be interpreted as a large, compared to some model estimates, muon-proton spin-independent contact interaction. The muonic hydrogen result can be tested by a muon-proton scattering experiment, MUSE, that is planned at the Paul Scherrer Institute in Switzerland. …

Designing And Building An Electromagnetic Mass Accelerator, David Appleberry

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Revitalizing Labs For Physics 115, Kayli Wood

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Passive Planar Terahertz Retroreflectors, Dhruvkumar Desai

Theses

As the application of the Terahertz (THz) band (0.1 - 10 THz) is investigated in various settings, wireless communication stands out as an important frontier to explore. The benefits of increased bandwidth and data rates it promises will only be realized if new technology is developed to support it. Specifically, since THz wireless communication links are typically line-of-sight (LoS), the LoS can be blocked by moving obstacles, thereby requiring alternative link paths. One proposed solution for indoor wireless communications involves systems of steerable antennas, reflective "wallpaper", and steerable mirrors which would redirect THz beams around a blocking obstacle.

As an …

Spin-Polarized Electron Transmission Through Chiral Halocamphor Molecules, J. M. Dreiling, F. W. Lewis, Timothy J. Gay

Timothy J. Gay Publications

We have measured electron-circularly-dichroic asymmetries when longitudinally-polarized (chiral) electrons are scattered quasi-elastically by chiral halocamphor molecules: 3-bromocamphor (C₁₀H₁₅BrO), 3-iodocamphor (C₁₀H₁₅IO), and 10-iodocamphor. The proposed dynamic origins of these asymmetries are considered in terms of three classical models related to Mott scattering, target electron helicity density, and spin-other-orbit interactions. The asymmetries observed for 3-bromocamphor and 3-iodocamphor scale roughly as Z², where Z is the nuclear charge of the heaviest atom in the target molecule, but the scaling is violated by 10- iodocamphor, which has a smaller asymmetry than that for 3-iodocamphor. …

Magnetism Of New Metastable Cobalt-Nitride Compounds, Balamuruga Balamurugan, Xin Zhao, Shah R. Valloppilly, Sumit Beniwal, Ralph Skomski, Anandakumar Sarella, Yunlong Jin, Xingzhong Li, Xiaoshan Xu, Huibo Cao, Haohan Wang, Axel Enders, Cai-Zhuang Wang, Kai-Ming Ho, David J. Sellmyer

Nebraska Center for Materials and Nanoscience: Faculty Publications

The search for new magnetic materials with high magnetization and magnetocrystalline anisotropy is important for a wide range of applications including information and energy processing. There is only a limited number of naturally occurring magnetic compounds that are suitable. This situation stimulates an exploration of new phases that occur far from thermal-equilibrium conditions, but their stabilization is generally inhibited due to high positive formation energies. Here a nanocluster-deposition method has enabled the discovery of a set of new non-equilibrium Co-N intermetallic compounds. The experimental search was assisted by computational methods including adaptive-genetic-algorithm and electronic- structure calculations. Conventional wisdom is that …

Motion-Induced Artifact Mitigation And Image Enhancement Strategies For Four-Dimensional Fan-Beam And Cone-Beam Computed Tomography, Matthew J. Riblett

Theses and Dissertations

Four dimensional imaging has become part of the standard of care for diagnosing and treating non-small cell lung cancer. In radiotherapy applications 4D fan-beam computed tomography (4D-CT) and 4D cone-beam computed tomography (4D-CBCT) are two advanced imaging modalities that afford clinical practitioners knowledge of the underlying kinematics and structural dynamics of diseased tissues and provide insight into the effects of regular organ motion and the nature of tissue deformation over time. While these imaging techniques can facilitate the use of more targeted radiotherapies, issues surrounding image quality and accuracy currently limit the utility of these images clinically.

The purpose of …

Geodesic Structure In Schwarzschild Geometry With Extensions In Higher Dimensional Spacetimes, Ian M. Newsome

Theses and Dissertations

From Birkoff's theorem, the geometry in four spacetime dimensions outside a spherically symmetric and static, gravitating source must be given by the Schwarzschild metric. This metric therefore satisfies the Einstein vacuum equations. If the mass which gives rise to the Schwarzschild spacetime geometry is concentrated within a radius of r=2M, a black hole will form. Non-accelerating particles (freely falling) traveling through this geometry will do so along parametrized curves called geodesics, which are curved space generalizations of straight paths. These geodesics can be found by solving the geodesic equation. In this thesis, the geodesic structure in the Schwarzschild geometry …

Evaluating The Effectiveness Of Current Atmospheric Refraction Models In Predicting Sunrise And Sunset Times, Teresa Wilson

Dissertations, Master's Theses and Master's Reports

The standard value for atmospheric refraction on the horizon of 34', used in all publicly available sunrise and sunset calculators, is found to be inadequate. The assumptions behind atmospheric models that predict this value fail to account for real meteorological conditions. The result is an uncertainty of one to five minutes in sunrise and sunset predictions at mid-latitudes (0° - 55° N/S). A sunrise/set calculator that interchanges the refraction component by varying the refraction model was developed. Two atmospheric refraction models of increasing complexity were tested along with the standard value. The predictions were compared with data sets of observed …