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Full-Text Articles in Physics
Doping Poly[2-Methoxy-5-(2′-Ethylhexyloxy)-1,4-Phenylenevinylene] With Pbse Nanoparticles Or Fullerenes, D. K. Chambers, Zhaoyan Zhang, F. Khatkhatay, S. Karanam, Orhan Kizilkaya, Yaroslav B. Losovyj, Sandra Zivanovic Selmic
Doping Poly[2-Methoxy-5-(2′-Ethylhexyloxy)-1,4-Phenylenevinylene] With Pbse Nanoparticles Or Fullerenes, D. K. Chambers, Zhaoyan Zhang, F. Khatkhatay, S. Karanam, Orhan Kizilkaya, Yaroslav B. Losovyj, Sandra Zivanovic Selmic
Department of Physics and Astronomy: Faculty Publications
The positions of the molecular orbitals of the conjugated semiconducting polymer, poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), relative to the Fermi level, shift when lead selenide (PbSe) quantum dots or the fullerene based molecule [(6)]-1-(3-(methoxycarbonyl)propyl)-[(5)]-1-phenyl-[5,6]-C61, known as PCBM, are dispersed in the polymer host. This is evident from the consistent shifts of occupied molecular orbitals and the valence band edge to greater binding energies and a decrease in density of states near the Fermi level, as probed by photoemission. In the case of PbSe nanocrystal quantum dots, far smaller binding energy shifts were observed. This behavior seems more characteristic of a charge donor, though …
Magnetic Spin Valve With A Magnetoelectric Element: Us Patent 7,358,846, Bernard Doudin
Magnetic Spin Valve With A Magnetoelectric Element: Us Patent 7,358,846, Bernard Doudin
Department of Physics and Astronomy: Faculty Publications
The present invention provides systems and method utilizing magnetoelectric materials such as Cr2O3 to construct tunneling magnetoresistence andor giant magnetoresistence structures for memory andor logical circuitry. An applied voltage differential induces a magnetic moment in the magnetoelectric material, which in turn tunes an exchange field between it and one or more adjacent ferromagnetic layers. The resulting magnetoresistence of the device may be measured. Devices in accordance with the present invention may be utilized for MRAM read heads, memory storage cells andor logical circuitry such as XOR or NXOR devices.
In Situ Measurement Of Three-Dimensional Ion Densities In Focused Femtosecond Pulses, James Strohaber, Cornelis J. Uiterwaal
In Situ Measurement Of Three-Dimensional Ion Densities In Focused Femtosecond Pulses, James Strohaber, Cornelis J. Uiterwaal
Department of Physics and Astronomy: Faculty Publications
We image spatial distributions of Xeq+ ions in the focus of a laser beam of ultrashort, intense pulses in all three dimensions, with a resolution of ~3μm and ~12 μm in the two transverse directions. This allows for studying ionization processes without spatially averaging ion yields. Our in situ ion imaging is also useful to analyze focal intensity profiles and to investigate the transverse modal purity of tightly focused beams of complex light. As an example, the intensity profile of a Hermite-Gaussian beam mode HG1,0 recorded with ions is found to be in good …
Relativistic Magnetic Monopole Flux Constraints From Rice, Daniel P. Hogan, Dave Z. Besson, John P. Ralston, Ilya Kravchenko, D. Seckel
Relativistic Magnetic Monopole Flux Constraints From Rice, Daniel P. Hogan, Dave Z. Besson, John P. Ralston, Ilya Kravchenko, D. Seckel
Department of Physics and Astronomy: Faculty Publications
We report an upper limit on the flux of relativistic monopoles based on the nonobservation of in-ice showers by the Radio Ice Cherenkov Experiment (RICE) at the South Pole.We obtain a 95% C.L. limit of order 10-18 (cm2 s sr)-1 for intermediate-mass monopoles of 107 ≤ γ ≤ 1012 at the anticipated energy Etot = 1016 GeV. This bound is over an order of magnitude stronger than all previously published experimental limits for this range of boost parameters γ and exceeds 2 orders of magnitude improvement over most of the range. We review …
Theory Of The Piezomagnetic Effect In Mn-Based Antiperovskites, Pavel Lukashev, Renat F. Sabirianov, Kirill D. Belashchenko
Theory Of The Piezomagnetic Effect In Mn-Based Antiperovskites, Pavel Lukashev, Renat F. Sabirianov, Kirill D. Belashchenko
Department of Physics and Astronomy: Faculty Publications
Recent experimental and theoretical studies of the magnetoelectric (ME) effect in the nanocomposite structures and in laminates show an enhanced ME coefficient. These materials combine piezoelectric properties of the paramagnetic phase and piezomagnetic properties of the magnetic phase. We propose to fabricate heterostructures formed by piezoelectric materials and magnetic antiperovskites as magnetoelectric materials. We show that the magnetic structure of antiperovskite, such as Mn3GaN, can be controlled by a small applied biaxial strain. The lowering of symmetry with the strain causes the local magnetic moments of Mn atoms to rotate from the trigonal Γ5g structure with symmetric …
Relativistic Magnetic Monopole Flux Constraints From Rice, Daniel P. Hogan, Dave Z. Besson, John P. Ralston, Ilya Kravchenko, D. Seckel
Relativistic Magnetic Monopole Flux Constraints From Rice, Daniel P. Hogan, Dave Z. Besson, John P. Ralston, Ilya Kravchenko, D. Seckel
Department of Physics and Astronomy: Faculty Publications
We report an upper limit on the flux of relativistic monopoles based on the nonobservation of in-ice showers by the Radio Ice Cherenkov Experiment (RICE) at the South Pole. We obtain a 95% C.L. limit of order 10-18(cm2 s sr)-1 for intermediate-mass monopoles of 107 ≤ γ ≤ 1012 at the anticipated energy Etot = 1016 GeV. This bound is over an order of magnitude stronger than all previously published experimental limits for this range of boost parameters γ and exceeds 2 orders of magnitude improvement over most of the range. We …
Aharonov–Bohm Phase Shifts Induced By Laser Pulses, Brett E. Barwick, Herman Batelaan
Aharonov–Bohm Phase Shifts Induced By Laser Pulses, Brett E. Barwick, Herman Batelaan
Department of Physics and Astronomy: Faculty Publications
An experimentally accessible scalar Aharonov–Bohm (AB)-effect is proposed using a ponderomotive potential induced by a pulsed laser. This ponderomotive AB (PAB)-effect is unique in that the time-averaged description is classified as type-I, whereas the underlying time-dependent theory is classified as type-II. Not only is the PAB-effect of fundamental interest, it may also be used to characterize ultrashort electron pulses (fs), using low power femtosecond lasers, which is important for ultrafast electron diffraction and microscopy.
Thermodynamics Of Itinerant Magnets In A Classical Spin-Fluctuation Model, Aleksander L. Wysocki, James K. Glasbrenner, Kirill D. Belashchenko
Thermodynamics Of Itinerant Magnets In A Classical Spin-Fluctuation Model, Aleksander L. Wysocki, James K. Glasbrenner, Kirill D. Belashchenko
Department of Physics and Astronomy: Faculty Publications
Thermodynamics of itinerant magnets is studied using a classical model with one parameter characterizing the degree of itinerancy. Monte Carlo simulations for bcc and fcc lattices are compared with the mean-field approximation and with the Onsager cavity field approximation extended to itinerant systems. The qualitative features of thermodynamics are similar to the known results of the functional integral method. It is found that magnetic short-range order is weak and almost independent on the degree of itinerancy, and the mean-field approximation describes the thermodynamics reasonably well. Ambiguity of the phase space measure for classical models is emphasized. The Onsager cavity field …