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Full-Text Articles in Physics
The Aharonov-Bohm Effects: Variations On A Subtle Theme, Herman Batelaan, Akira Tonomura
The Aharonov-Bohm Effects: Variations On A Subtle Theme, Herman Batelaan, Akira Tonomura
Department of Physics and Astronomy: Faculty Publications
The notion, introduced 50 years ago, that electrons could be affected by electromagnetic potentials without coming in contact with actual force fields was received with a skepticism that has spawned a flourishing of experimental tests and expansions of the original idea.
First-Principles Analysis Of Spin-Disorder Resistivity Of Fe And Ni, Aleksander L. Wysocki, Renat F. Sabirianov, Mark Van Schilfgaarde, Kirill D. Belashchenko
First-Principles Analysis Of Spin-Disorder Resistivity Of Fe And Ni, Aleksander L. Wysocki, Renat F. Sabirianov, Mark Van Schilfgaarde, Kirill D. Belashchenko
Department of Physics and Astronomy: Faculty Publications
Spin-disorder resistivity of Fe and Ni and its temperature dependence are analyzed using noncollinear density functional calculations within the supercell method. Different models of thermal spin disorder are considered, including the mean-field approximation and the nearest-neighbor Heisenberg model. If the local moments are kept frozen at their zero-temperature values, very good agreement with experiment is obtained for Fe but for Ni the resistivity at elevated temperatures is significantly overestimated. Agreement with experiment for Fe is improved if the local moments are made self-consistent. The effect of short-range order on spindisorder resistivity is more pronounced in Ni compared to Fe but …
Magnetism Of Chromia From First-Principles Calculations, Siqi Shi, Aleksander L. Wysocki, Kirill D. Belashchenko
Magnetism Of Chromia From First-Principles Calculations, Siqi Shi, Aleksander L. Wysocki, Kirill D. Belashchenko
Department of Physics and Astronomy: Faculty Publications
The electronic structure and magnetism of chromia (corundum-type Cr2O3) are studied using full-potential first-principles calculations. The electronic correlations are included within the LSDA+U method. The energies of different magnetic configurations are very well fitted by the Heisenberg Hamiltonian with strong exchange interaction with two nearest neighbors and additional weak interaction up to the fifth neighbor shell. These energies are insensitive to the position of the oxygen states, indicating that magnetism in Cr2O3 is dominated by direct exchange. The Néel temperature is calculated using the pair-cluster approximation for localized quantum spins of magnitude 3/2. …
Voltage-Induced Switching With Magnetoresistance Signature In Magnetic Nano-Filaments, Andrei Sokolov, Renat F. Sabirianov, Ildar F. Sabiryanov, Bernard Doudin
Voltage-Induced Switching With Magnetoresistance Signature In Magnetic Nano-Filaments, Andrei Sokolov, Renat F. Sabirianov, Ildar F. Sabiryanov, Bernard Doudin
Department of Physics and Astronomy: Faculty Publications
Large hysteretic resistance changes are reported on sub-100 nm diameter metallic nanowires including thin dielectric junctions. Bi-stable 50% switching in a double junction geometry is modeled in terms of an occupation-driven metal–insulator transition in one of the two junctions, using the generalized Poisson expressions of Oka and Nagaosa (2005 Phys. Rev. Lett. 95 266403). It illustrates how a band bending scheme can be generalized for strongly correlated electron systems. The magnetic constituents of the nanowires provide a magnetoresistive signature of the two resistance states, confirming our model and enabling a four states device application.
Feynman’S Relativistic Electrodynamics Paradox And The Aharonov-Bohm Effect, Adam Caprez, Herman Batelaan
Feynman’S Relativistic Electrodynamics Paradox And The Aharonov-Bohm Effect, Adam Caprez, Herman Batelaan
Department of Physics and Astronomy: Faculty Publications
An analysis is done of a relativistic paradox posed in the Feynman Lectures of Physics involving two interacting charges. The physical system presented is compared with similar systems that also lead to relativistic paradoxes. The momentum conservation problem for these systems is presented. The relation between the presented analysis and the ongoing debates on momentum conservation in the Aharonov-Bohm problem is discussed.
Nonlinear Laser Energy Depletion In Laser-Plasma Accelerators, Bradley Allan Shadwick, Carl B. Schroeder, Eric Esarey
Nonlinear Laser Energy Depletion In Laser-Plasma Accelerators, Bradley Allan Shadwick, Carl B. Schroeder, Eric Esarey
Department of Physics and Astronomy: Faculty Publications
Energy depletion of intense, short-pulse lasers via excitation of plasma waves is investigated numerically and analytically. The evolution of a resonant laser pulse proceeds in two phases. In the first phase, the pulse steepens, compresses, and frequency redshifts as energy is deposited in the plasma. The second phase of evolution occurs after the pulse reaches a minimum length at which point the pulse rapidly lengthens, losing resonance with the plasma. Expressions for the rate of laser energy loss and rate of laser redshifting are derived and are found to be in excellent agreement with the direct numerical solution of the …
A Wide-Angle Electron Grating Bi-Prism Beam Splitter, Adam Caprez, Roger Bach, Scot Mcgregor, Herman Batelaan
A Wide-Angle Electron Grating Bi-Prism Beam Splitter, Adam Caprez, Roger Bach, Scot Mcgregor, Herman Batelaan
Department of Physics and Astronomy: Faculty Publications
We demonstrate a wide-angle electron beam splitter capable of producing 1 cm beam separation at the detection plane. The beam splitter utilizes a nanofabricated periodic grating in combination with a bi-prism element. In contrast to devices utilizing only bi-prism elements, the use of the periodic grating causes amplitude, and not wavefront, splitting. Even at maximum separation, beam profiles remain undistorted, providing evidence that coherence is intact. This is a step towards the realization of a large area electron interferometer using such a grating bi-prism combination.