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Articles 121 - 150 of 191
Full-Text Articles in Atomic, Molecular and Optical Physics
Radiation Therapy Medical Physics Review – Delivery, Interactions, Safety, Feasibility, And Head To Head Comparisons Of The Leading Radiation Therapy Techniques, Cielle Collins
Honors Theses and Capstones
Radiation therapy uses high energy radiation to kill cancer cells. Radiation therapy for cancer treatment can take the form of photon therapy (using x-rays and gamma rays), or charged particle therapy including proton therapy and electron therapy. Within these categories, numerous methods of delivery have been developed. For example, a certain type of radiation can be administered by a machine outside of the body, called external-beam radiation therapy, or by a “seed” placed inside of the body near cancer cells, called internal radiation therapy or brachytherapy. Approximately half of all cancer patients receive radiation therapy, and the form of radiation …
Domain Formation Mechanism Of The Si(110) “16 × 2” Reconstruction, N. K. Lewis, Nathan B. Clayburn, Evan M. Brunkow, Timothy J. Gay, Y. Lassailly, J. Fujii, I. Vobornik, W. R. Flavell, E. A. Seddon
Domain Formation Mechanism Of The Si(110) “16 × 2” Reconstruction, N. K. Lewis, Nathan B. Clayburn, Evan M. Brunkow, Timothy J. Gay, Y. Lassailly, J. Fujii, I. Vobornik, W. R. Flavell, E. A. Seddon
Timothy J. Gay Publications
The main factor that determines which of the two domains forms upon reconstruction of the Si(110) “16 × 2” surface has been investigated. Low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM) images showed that the domain orientation was independent of the heating current direction used to induce the Si(110) “16 × 2” reconstruction. Reciprocal-space lattice models of the reconstruction allowed for the correct identification of domain orientations in the LEED images, and they confirmed that the reconstruction is two dimensionally chiral. It is proposed that the domain orientation upon surface reconstruction is determined by the direction of monatomic steps …
Magnetism In Curved Geometries, Robert Streubel, Peter Fischer, Florian Kronast, Volodymyr P. Kravchuk, Denis D. Sheka, Yuri Gaididei, Oliver G. Schmidt, Denys Makarov
Magnetism In Curved Geometries, Robert Streubel, Peter Fischer, Florian Kronast, Volodymyr P. Kravchuk, Denis D. Sheka, Yuri Gaididei, Oliver G. Schmidt, Denys Makarov
Robert Streubel Papers
Extending planar two-dimensional structures into the three-dimensional space has become a general trend in multiple disciplines, including electronics, photonics, plasmonics and magnetics. This approach provides means to modify conventional or to launch novel functionalities by tailoring the geometry of an object, e.g. its local curvature. In a generic electronic system, curvature results in the appearance of scalar and vector geometric potentials inducing anisotropic and chiral effects. In the specific case of magnetism, even in the simplest case of a curved anisotropic Heisenberg magnet, the curvilinear geometry manifests two exchange-driven interactions, namely effective anisotropy and antisymmetric exchange, i.e. Dzyaloshinskii-Moriya-like interaction. As …
Spica: Stereographic Projection For Interactive Crystallographic Analysis, Xingzhong Li
Spica: Stereographic Projection For Interactive Crystallographic Analysis, Xingzhong Li
Nebraska Center for Materials and Nanoscience: Faculty Publications
In numerous research fields, especially the applications of electron and X-ray diffraction, stereographic projection represents a powerful tool for researchers. SPICA is a new computer program for stereographic projection in interactive crystallographic analysis, which inherits features from the previous JECP/SP and includes more functions for extensive crystallographic analysis. SPICA provides fully interactive options for users to plot stereograms of crystal directions and crystal planes, traces, and Kikuchi maps for an arbitrary crystal structure; it can be used to explore the orientation relationships between two crystalline phases with a composite stereogram; it is also used to predict the tilt angles of …
Model For The Electrolysis Of Water And Its Use For Optimization, Roger Lascorz, Javier E. Hasbun Dr
Model For The Electrolysis Of Water And Its Use For Optimization, Roger Lascorz, Javier E. Hasbun Dr
Georgia Journal of Science
The goal of this research was to study the optimization of the electrolysis of water both theoretically and experimentally. For accuracy, 3 hr experiments were made with measurements recorded every 15 min. The results show that a better model than the classical one is needed for water electrolysis. A new model that fits experimental data better is proposed. The results of this new model not only predict hydrogen production in electrolysis of water better, but show a way to predict gas production of any liquid as well as what voltage to use to optimize it.
A Cylindrically Symmetric “Micro-Mott” Electron Polarimeter, Nathan B. Clayburn, Evan M. Brunkow, S. J. Burtwistle, George H. Rutherford, Timothy J. Gay
A Cylindrically Symmetric “Micro-Mott” Electron Polarimeter, Nathan B. Clayburn, Evan M. Brunkow, S. J. Burtwistle, George H. Rutherford, Timothy J. Gay
Timothy J. Gay Publications
A small, novel, cylindrically symmetric Mott electron polarimeter is described. The effective Sherman function, Seff , or analyzing power, for 20 kV Au target bias with a 1.3 keV energy loss window is 0.16 ± 0.01, where uncertainty in the measurement is due primarily to uncertainty in the incident electron polarization. For an energy loss window of 0.5 keV, Seff reaches its maximum value of 0.24 ± 0.02. The device’s maximum efficiency, I/Io, defined as the detected count rate divided by the incident particle rate, is 3.7 ± 0.2 × 10− …
New Type Of Al-Based Decagonal Quasicrystal In Al60Cr20Fe10Si10 Alloy, Zhanbing He, Haikun Ma, Hua Li, Xingzhong Li, Xiuliang Ma
New Type Of Al-Based Decagonal Quasicrystal In Al60Cr20Fe10Si10 Alloy, Zhanbing He, Haikun Ma, Hua Li, Xingzhong Li, Xiuliang Ma
Nebraska Center for Materials and Nanoscience: Faculty Publications
A new kind of decagonal quasicrystal (DQC) with a periodicity of 1.23 nm was observed in the as-cast quaternary Al60Cr20Fe10Si10 alloy. The intensity distribution of some spots in the selected-area electron diffraction pattern along the tenfold zone axis was found to be different from other Al-based DQCs. High-angle annular dark-field scanning transmission electron microscopy was adopted to reveal the structural features at an atomic level. Both the tenfold symmetry and symmetry-broken decagonal (D) clusters of 1.91 nm in diameter were found, but with structural characteristics different from the corresponding D clusters in the …
Vortex Circulation And Polarity Patterns In Closely Packed Cap Arrays, Robert Streubel, Florian Kronast, Christopher F. Reiche, Thomas Mühl, Anja U.B. Wolter, Oliver G. Schmidt, Denys Makarov
Vortex Circulation And Polarity Patterns In Closely Packed Cap Arrays, Robert Streubel, Florian Kronast, Christopher F. Reiche, Thomas Mühl, Anja U.B. Wolter, Oliver G. Schmidt, Denys Makarov
Robert Streubel Papers
We studied curvature-driven modifications to the magnetostatic coupling of vortex circulation and polarity in soft-magnetic closely packed cap arrays. A phase diagram for the magnetic remanent/transition states at room temperature as a function of diameter and thickness was assembled. For specimens with vortex remanent state (40 nm-thick Permalloy on 330 nm spherical nanoparticles), both vortex circulation and polarity were visualized. Intercap coupling upon vortex nucleation leads to the formation of vortex circulation patterns in closely packed arrays. The remanent circulation pattern can be tailored choosing the direction of the applied magnetic field with respect to the symmetry axis of the …
Anomalously Large Chiral Sensitivity In The Dissociative Electron Attachment Of 10-Iodocamphor, J. M. Dreiling, F. W. Lewis, J. D. Mills, Timothy J. Gay
Anomalously Large Chiral Sensitivity In The Dissociative Electron Attachment Of 10-Iodocamphor, J. M. Dreiling, F. W. Lewis, J. D. Mills, Timothy J. Gay
Timothy J. Gay Publications
We have studied dissociative electron attachment (DEA) between low energy (≤ 0.6 eV) longitudinally polarized electrons and gas-phase chiral targets of 3-bromocamphor (C10H15BrO), 3-iodocamphor (C10H15IO), and 10-iodocamphor. The DEA rate depends on the sign of the incident electron helicity for a given target handedness, and it varies with both the atomic number (Z) and location of the heaviest atom in the molecule. While simple dynamic mechanisms can account for the asymmetry dependence on Z, they fail to explain the large asymmetry variation with the heavy atom location.
Electron Diffraction Study Of Cobalt-Rich Hf-Co, Xingzhong Li, Yunlong Jin, Jeffrey E. Shield, Ralph Skomski, David J. Sellmyer
Electron Diffraction Study Of Cobalt-Rich Hf-Co, Xingzhong Li, Yunlong Jin, Jeffrey E. Shield, Ralph Skomski, David J. Sellmyer
Nebraska Center for Materials and Nanoscience: Faculty Publications
Intermetallic compounds having compositions from HfCo4 to HfCo8 were investigated by transmission electron microscopy, selected-area electron diffraction, and energy-dispersive x-ray spectroscopy. A major crystalline phase, closely related to the orthorhombic Zr2Co11 phase in structure, has been observed in the samples with the composition ranges from HfCo6 to HfCo8. The phase, referred to as either Hf2Co11 or HfCo7 phase in the literature, is actually one common phase, having a broad composition range and referred to as μ-phase in the present paper. In addition to the μ-phase, we …
Method For Monitoring Gaas Photocathode Heat Cleaning Temperature, Nathan B. Clayburn, Kenneth Wayne Trantham, M. Dunn, Timothy J. Gay
Method For Monitoring Gaas Photocathode Heat Cleaning Temperature, Nathan B. Clayburn, Kenneth Wayne Trantham, M. Dunn, Timothy J. Gay
Timothy J. Gay Publications
Before a GaAs photocathode can be activated to achieve a negative electron affinity condition, the GaAs crystal must be cleaned. This is most commonly done by ohmic, radiative, or electron bombardment heating. We report a new technique to monitor the temperature of heated GaAs photocathodes by observation with a camera. The method is robust and yields the same temperatures for different GaAs samples heated using different methods in different mounting configurations.
Phase Separation In Lufeo3 Films, Shi Cao, Xiaozhe Zhang, Kishan Sinha, Wenbin Wang, Jian Wang, Peter A. Dowben, Xiaoshan Xu
Phase Separation In Lufeo3 Films, Shi Cao, Xiaozhe Zhang, Kishan Sinha, Wenbin Wang, Jian Wang, Peter A. Dowben, Xiaoshan Xu
Peter Dowben Publications
The structural transition at about 1000°C, from the hexagonal to the orthorhombic phase of LuFeO3, has been investigated in thin films of LuFeO3. Separation of the two structural phases of LuFeO3 occurs on a length scale of micrometer, as visualized in real space using X-ray photoemission electron microscopy. The results are consistent with X-ray diffraction and atomic force microscopy obtained from LuFeO3 thin films undergoing the irreversible structural transition from the hexagonal to the orthorhombic phase of LuFeO3, at elevated temperatures. The sharp phase boundaries between the structural phases are observed to …
Influence Of Steric Hindrance On The Molecular Packing And The Anchoring Of Quinonoid Zwitterions On Gold Surfaces, Minghui Yuan, Iori Tababe, Jean-Marie Bernard- Schaaf, Qin-Yin Shi, Vicki Schlegel, Rachel Schurhammer, Peter A. Dowben, Bernard Doudin, Lucie Routaboul, Pierre Braunstein
Influence Of Steric Hindrance On The Molecular Packing And The Anchoring Of Quinonoid Zwitterions On Gold Surfaces, Minghui Yuan, Iori Tababe, Jean-Marie Bernard- Schaaf, Qin-Yin Shi, Vicki Schlegel, Rachel Schurhammer, Peter A. Dowben, Bernard Doudin, Lucie Routaboul, Pierre Braunstein
Peter Dowben Publications
Driven by the huge potential of engineering the molecular band offset with highly dipolar molecules for improving charge injection into organic electrics, the anchoring of various N-alkyl substituted quinonoid zwitterions of formula C6H2 (···NHR)2 (···O)2 (R = iPr, Cy, CH2CH(Et)CH2CH2CH2CH3,. . .) on gold surfaces is studied. The N–Au interactions result in an orthogonal arrangement of the zwitterions cores with respect to the surface, and stabilize adsorbed compact rows of molecules. IR spectroscopy is used as a straightforward diagnostic tool to validate the presence of …
On The Ising Character Of The Quantum-Phase Transition In Lihof4, Ralph Skomski
On The Ising Character Of The Quantum-Phase Transition In Lihof4, Ralph Skomski
Ralph Skomski Publications
It is investigated how a transverse magnetic field affects the quantum-mechanical character of LiHoF4, a system generally considered as a textbook example for an Ising-like quantum-phase transition. In small magnetic fields, the low-temperature behavior of the ions is Ising-like, involving the nearly degenerate low-lying Jz = ± 8 doublet. However, as the transverse field increases, there is a substantial admixture of states having | Jz | < 8. Near the quantum-phase-transition field, the system is distinctively non-Ising like, and all Jz eigenstates yield ground-state contributions of comparable magnitude. A classical analog to this mechanism is the micromagnetic single point in magnets with uniaxial anisotropy. Since Ho3+ has …
Domain Wall Conductivity In Semiconducting Hexagonal Ferroelectric Tbmno3 Thin Films, D. J. Kim, J. G. Connell, S. S. A. Seo, Alexei Gruverman
Domain Wall Conductivity In Semiconducting Hexagonal Ferroelectric Tbmno3 Thin Films, D. J. Kim, J. G. Connell, S. S. A. Seo, Alexei Gruverman
Alexei Gruverman Publications
Although enhanced conductivity of ferroelectric domain boundaries has been found in BiFeO3 and Pb(Zr,Ti)O3 films as well as hexagonal rare-earth manganite single crystals, the mechanism of the domain wall conductivity is still under debate. Using conductive atomic force microscopy, we observe enhanced conductance at the electrically-neutral domain walls in semiconducting hexagonal ferroelectric TbMnO3 thin films where the structure and polarization direction are strongly constrained along the c-axis. This result indicates that domain wall conductivity in ferroelectric rare-earth manganites is not limited to charged domain walls. We show that the observed conductivity in the TbMnO3 films is …
Low-Temperature Fcc To L10 Phase Transformation In Copt(Bi) Nanoparticles, Frank M. Abel, Vasilis Tzitzios, David J. Sellmeyer, George C. Hadjipanayis
Low-Temperature Fcc To L10 Phase Transformation In Copt(Bi) Nanoparticles, Frank M. Abel, Vasilis Tzitzios, David J. Sellmeyer, George C. Hadjipanayis
Nebraska Center for Materials and Nanoscience: Faculty Publications
This work is focused on the effects of Bi substitution on the synthesis of CoPt nanoparticles with the L10 structure using a modified organometallic approach. The structural and magnetic properties of the nanoparticles have been studied and compared directly with those of CoPt nanoparticles synthesized by the same tech- nique but in the absence of Bi substitution. The as-synthesized particles at 330 ◦C have an average size of 11.7 nm and a partially ordered L10 phase with a coercivity of 1 kOe. The coercivity is increased to 9.3 kOe and 12.4 kOe after annealing for 1 hour at 600 …
Modification Of The G-Phonon Mode Of Graphene By Nitrogen Doping, Pavel V. Lukashev, Liuyan Zhao, Tula R. Paudel, Theanne Schiros, Noah Hurley, Evgeny Y. Tsymbal, Aron Pinczuk, Abhay Pasupathy, Rui He
Modification Of The G-Phonon Mode Of Graphene By Nitrogen Doping, Pavel V. Lukashev, Liuyan Zhao, Tula R. Paudel, Theanne Schiros, Noah Hurley, Evgeny Y. Tsymbal, Aron Pinczuk, Abhay Pasupathy, Rui He
Nebraska Center for Materials and Nanoscience: Faculty Publications
The effect of nitrogen doping on the phonon spectra of graphene is analyzed. In particular, we employ first-principles calculations and scanning Raman analysis to investigate the dependence of phonon frequencies in graphene on the concentration of nitrogen dopants. We demonstrate that the G phonon frequency shows oscillatory behavior as a function of nitrogen concentration. We analyze different mechanisms which could potentially be responsible for this behavior, such as Friedel charge oscillations around the localized nitrogen impurity atom, the bond length change between nitrogen impurity and its nearest neighbor carbon atoms, and the long-range interactions of the nitrogen point defects. We …
Structure And Magnetism Of New Rare- Earth-Free Intermetallic Compounds: Fe3+Xco3−Xti2 (0 ≤ X ≤ 3), Balamurugan Balamurugan, Bhaskar Das, Manh Cuong Ngyuen, Xiaoshan Xu, Jie Zhang, Xiaozhe Zhang, Yaohua Liu, Ashfia Huq, Shah R. Valloppilly, Yunlong Jin, Cai-Zhuang Wang, Kai-Ming Ho, David J. Sellmyer
Structure And Magnetism Of New Rare- Earth-Free Intermetallic Compounds: Fe3+Xco3−Xti2 (0 ≤ X ≤ 3), Balamurugan Balamurugan, Bhaskar Das, Manh Cuong Ngyuen, Xiaoshan Xu, Jie Zhang, Xiaozhe Zhang, Yaohua Liu, Ashfia Huq, Shah R. Valloppilly, Yunlong Jin, Cai-Zhuang Wang, Kai-Ming Ho, David J. Sellmyer
Nebraska Center for Materials and Nanoscience: Faculty Publications
We report the fabrication of a set of new rare-earth-free magnetic compounds, which form the Fe3Co3Ti2-type hexagonal structure with P-6m2 symmetry. Neutron powder diffraction shows a significant Fe/Co anti-site mixing in the Fe3Co3Ti2 structure, which has a strong effect on the magnetocrystalline anisotropy as revealed by first-principle calculations. Increasing substitution of Fe atoms for Co in the Fe3Co3Ti2 lattice leads to the formation of Fe4Co2Ti2 , Fe5CoTi, and Fe6Ti2 with significantly improved …
Reconfigurable Large-Area Magnetic Vortex Circulation Patterns, Robert Streubel, Florian Kronast, Ulrich K. Rößler, Oliver G. Schmidt, Denys Makarov
Reconfigurable Large-Area Magnetic Vortex Circulation Patterns, Robert Streubel, Florian Kronast, Ulrich K. Rößler, Oliver G. Schmidt, Denys Makarov
Robert Streubel Papers
Magnetic vortices in nanodots own a switchable circulation sense. These nontrivial magnetization configurations can be arranged into extended and interacting patterns. We have experimentally created large arrays of magnetically reconfigurable vortex patterns in nonplanar honeycomb lattices using particle lithography. Optimizing height asymmetry of the vertices and applying an in-plane magnetic field provide means to switch between homocircular and staggered vortex patterns with a potentially high impact on magnonics and spintronics relying on chiral noncollinear spin textures. To this end, exchange coupling of extended vortex lattices with an out-of-plane magnetized layer allows one to realize artificial skyrmionic core textures with controllable …
Magnetization Dynamics Of Imprinted Non-Collinear Spin Textures, Robert Streubel, Peter Fischer, Martin Kopte, Oliver G. Schmidt, Denys Makarov
Magnetization Dynamics Of Imprinted Non-Collinear Spin Textures, Robert Streubel, Peter Fischer, Martin Kopte, Oliver G. Schmidt, Denys Makarov
Robert Streubel Papers
We study the magnetization dynamics of non-collinear spin textures realized via imprint of the magnetic vortex state in soft permalloy into magnetically hard out-of-plane magnetized Co/Pd nanopatterned heterostructures. Tuning the interlayer exchange coupling between soft- and hard-magnetic subsystems provides means to tailor the magnetic state in the Co/Pd stack from being vortex- to donut-like with different core sizes. While the imprinted vortex spin texture leads to the dynamics similar to the one observed for vortices in permalloy disks, the donut-like state causes the appearance of two gyrofrequencies characteristic of the early and later stages of the magnetization dynamics. The dynamics …
Retrieving Spin Textures On Curved Magnetic Thin Films With Full-Field Soft X-Ray Microscopies, Robert Streubel, Florian Kronast, Peter Fischer, Dula Parkinson, Oliver G. Schmidt, Denys Makarov
Retrieving Spin Textures On Curved Magnetic Thin Films With Full-Field Soft X-Ray Microscopies, Robert Streubel, Florian Kronast, Peter Fischer, Dula Parkinson, Oliver G. Schmidt, Denys Makarov
Robert Streubel Papers
X-ray tomography is a well-established technique to characterize 3D structures in material sciences and biology; its magnetic analogue - magnetic X-ray tomography - is yet to be developed. Here we demonstrate the visualization and reconstruction of magnetic domain structures in a 3D curved magnetic thin films with tubular shape by means of full-field soft X-ray microscopies. The 3D arrangement of the magnetization is retrieved from a set of 2D projections by analysing the evolution of the magnetic contrast with varying projection angle. Using reconstruction algorithms to analyse the angular evolution of 2D projections provides quantitative information about domain patterns and …
Electrostatic Charge On Flying Hummingbirds And Its Potential Role In Pollination, Marc Badger, Victor Manuel Ortega-Jimenez, Lisa Von Ribenau, Ashley Smiley, Robert Dudley, Alexei Gruverman , Editor
Electrostatic Charge On Flying Hummingbirds And Its Potential Role In Pollination, Marc Badger, Victor Manuel Ortega-Jimenez, Lisa Von Ribenau, Ashley Smiley, Robert Dudley, Alexei Gruverman , Editor
Alexei Gruverman Publications
Electrostatic phenomena are known to enhance both wind- and insect-mediated pollination, but have not yet been described for nectar-feeding vertebrates. Here we demonstrate that wild Anna's Hummingbirds (Calypte anna) can carry positive charges up to 800 pC while in flight (mean ± s.d.: 66 ± 129 pC). Triboelectric charging obtained by rubbing an isolated hummingbird wing against various plant structures generated charges up to 700 pC. A metal hummingbird model charged to 400 pC induced bending of floral stamens in four plants (Nicotiana, Hemerocallis, Penstemon, and Aloe spp.), and also attracted falling Lycopodium spores at distances of < 2 mm. Electrostatic forces may therefore influence pollen transfer onto nectar-feeding birds.
Manipulating Topological States By Imprinting Non-Collinear Spin Textures, Robert Streubel, Luyang Han, Mi Young Im, Florian Kronast, Ulrich K. Rößler, Florin Radu, Radu Abrudan, Gungun Lin, Oliver G. Schmidt, Peter Fischer, Denys Makarov
Manipulating Topological States By Imprinting Non-Collinear Spin Textures, Robert Streubel, Luyang Han, Mi Young Im, Florian Kronast, Ulrich K. Rößler, Florin Radu, Radu Abrudan, Gungun Lin, Oliver G. Schmidt, Peter Fischer, Denys Makarov
Robert Streubel Papers
Topological magnetic states, such as chiral skyrmions, are of great scientific interest and show huge potential for novel spintronics applications, provided their topological charges can be fully controlled. So far skyrmionic textures have been observed in noncentrosymmetric crystalline materials with low symmetry and at low temperatures. We propose theoretically and demonstrate experimentally the design of spin textures with topological charge densities that can be tailored at ambient temperatures. Tuning the interlayer coupling in vertically stacked nanopatterned magnetic heterostructures, such as a model system of a Co/Pd multilayer coupled to Permalloy, the in-plane non-collinear spin texture of one layer can be …
Chirally-Sensitive Electron-Molecule Interactions, J. M. Dreiling, Timothy J. Gay
Chirally-Sensitive Electron-Molecule Interactions, J. M. Dreiling, Timothy J. Gay
Timothy J. Gay Publications
All molecular forms of life have chemically-specific handedness. However, the origin of these asymmetries is not understood. A possible explanation was suggested by Vester and Ulbricht immediately following the discovery of parity violation in 1957: chiral beta radiation in cosmic rays may have preferentially destroyed one enantiomeric form of various biological precursors. In the experiments reported here, we observed chiral specificity in two electronmolecule interactions: quasi-elastic scattering and dissociative electron attachment. Using lowenergy longitudinally spin-polarized (chiral) electrons as substitutes for beta rays, we found that chiral bromocamphor molecules exhibited both a transmission and dissociative electron attachment rate that depended on …
Magnetic Soft X-Ray Tomography Of Magnetic Swiss Roll Architectures, Robert Streubel, F. Kronast, P. Fischer, O. G. Schmidt, D. Makarov
Magnetic Soft X-Ray Tomography Of Magnetic Swiss Roll Architectures, Robert Streubel, F. Kronast, P. Fischer, O. G. Schmidt, D. Makarov
Robert Streubel Papers
A further increase in performance of state-of-the-art spin-electronics can be achieved by either miniaturizing its functional components or harnessing the third dimension. The first route, however, faces physical limitations as properties of nanostructures and their response to external stimuli can drastically change in reduced dimensions. An alternative way is to go from planar 2D structures to 3D architectures [1]. Such 3D functional elements can be obtained for example by rolling up initially planar strained thin films into Swiss roll like objects with multiple windings (Fig. 1a). A major advantage of this technology platform is the possibility to fabricate compact multifunctional …
Magnetic Force Microscopy Study Of Zr2co11-Based Nanocrystalline Materials: Effect Of Mo Addition, Lanping Yue, Yunlong Jin, Wenyong Zhang, David J. Sellmyer
Magnetic Force Microscopy Study Of Zr2co11-Based Nanocrystalline Materials: Effect Of Mo Addition, Lanping Yue, Yunlong Jin, Wenyong Zhang, David J. Sellmyer
Nebraska Center for Materials and Nanoscience: Faculty Publications
The addition of Molybdenum was used to modify the nanostructure and enhance coercivity of rare-earth-free Zr2Co11-based nanocrystalline permanent magnets. The effect of Mo addition on magnetic domain structures of melt spun nanocrystalline Zr16Co84−xMox (𝑥 = 0, 0.5, 1, 1.5, and 2.0) ribbons has been investigated. It was found that magnetic properties and local domain structures are strongly influenced by Mo doping. The coercivity of the samples increases with the increase in Mo content (𝑥 ≤ 1.5). The maximum energy product (𝐵𝐻)max increases with increasing 𝑥 from 0.5 MGOe for 𝑥 …
Magnetic Chiral Spin Textures By Imprinting, Robert Streubel, F. Kronast, U. Rössler, O. G. Schmidt, P. Fischer, D. Makarov
Magnetic Chiral Spin Textures By Imprinting, Robert Streubel, F. Kronast, U. Rössler, O. G. Schmidt, P. Fischer, D. Makarov
Robert Streubel Papers
The unique properties of non-trivial topological states, e.g. magnetic skyrmions [1] may path the way towards novel spintronic devices [2]. However, these spin textures have only been observed in special classes of materials possessing non-centrosymmetric crystal structure [1,3-6] and at low temperatures, which limits their application potential. We offer an alternate route to design synthetic magnetic heterostructures that resemble swirls, vortices or skyrmions with distinct topological charge densities at room temperature. By vertically stacking two magnetic nanopatterns with in-and out-of-plane magnetization and tailoring the interlayer exchange coupling, non-collinear spin textures with tunable topological charge can be imprinted (Fig. 1a).
Conservation Of The Spin And Orbital Angular Momenta In Electromagnetism, Konstantin Y. Bliokh, Justin Dressel, Franco Nori
Conservation Of The Spin And Orbital Angular Momenta In Electromagnetism, Konstantin Y. Bliokh, Justin Dressel, Franco Nori
Mathematics, Physics, and Computer Science Faculty Articles and Research
We review and re-examine the description and separation of the spin and orbital angular momenta (AM) of an electromagnetic field in free space. While the spin and orbital AM of light are not separately meaningful physical quantities in orthodox quantum mechanics or classical field theory, these quantities are routinely measured and used for applications in optics. A meaningful quantum description of the spin and orbital AM of light was recently provided by several authors, which describes separately conserved and measurable integral values of these quantities. However, the electromagnetic field theory still lacks corresponding locally conserved spin and orbital AM currents. …
Positive Exchange Bias In Epitaxial Permalloy/Mgo Integrated With Si (100), S. S. Rao, J. T. Prater, Fan Wu, S. Nori, D. Kumar, Lanping Yue, Sy_Hwang Liou, Jagdish Narayan
Positive Exchange Bias In Epitaxial Permalloy/Mgo Integrated With Si (100), S. S. Rao, J. T. Prater, Fan Wu, S. Nori, D. Kumar, Lanping Yue, Sy_Hwang Liou, Jagdish Narayan
Sy-Hwang Liou Publications
In magnetic random access memory (MRAM) devices, soft magnetic thin film elements such as permalloy (Py) are used as unit cells of information. The epitaxial integration of these elements with the technologically important substrate Si (100) and a thorough understanding of their magnetic properties are critical for CMOS-based magnetic devices. We report on the epitaxial growth of Ni82.5Fe17.5 (permalloy, Py) on Si (100) using a TiN/MgO buffer layer. Initial stages of growth are characterized by the formation of discrete islands that gradually merge into a continuous film as deposition times are extended. Interestingly, we find that the …
The Spin State Of A Molecular Adsorbate Driven By The Ferroelectric Substrate Polarization†, Xin Zhang, Tatiana Palamarciuc, Jean-François Létard, Patrick Rosa, Eduardo Vega Lozada, Fernand Torres, Luis G. Rosa, Bernard Doudin, Peter A. Dowben
The Spin State Of A Molecular Adsorbate Driven By The Ferroelectric Substrate Polarization†, Xin Zhang, Tatiana Palamarciuc, Jean-François Létard, Patrick Rosa, Eduardo Vega Lozada, Fernand Torres, Luis G. Rosa, Bernard Doudin, Peter A. Dowben
Peter Dowben Publications
The spin state of [Fe(H2B(pz)2)2(bipy)] thin films is mediated by changes in the electric field at the interface of organic ferroelectric polyvinylidene fluoride with trifluoroethylene (PVDF–TrFE). Signatures of the molecular crossover transition are evident in changes in the unoccupied states and the related shift from diamagnetic to paramagnetic characteristics. This may point the way to the molecular magneto-electric effect on devices.