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Full-Text Articles in Condensed Matter Physics
Decoherence And Recoherence In A Vibrating Rf Squid, Eyal Buks, M. P. Blencowe
Decoherence And Recoherence In A Vibrating Rf Squid, Eyal Buks, M. P. Blencowe
Dartmouth Scholarship
We study an rf SQUID, in which a section of the loop is a freely suspended beam that is allowed to oscillate mechanically. The coupling between the rf SQUID and the mechanical resonator originates from the dependence of the total magnetic flux threading the loop on the displacement of the resonator. Motion of the latter affects the visibility of Rabi oscillations between the two lowest energy states of the rf SQUID. We address the feasibility of experimental observation of decoherence and recoherence, namely decay and rise of the visibility, in such a system.
Transmission Electron Goniometry And Its Relation To Electron Tomography For Materials Science Apoplications, Peter Moeck, P. Fraundorf
Transmission Electron Goniometry And Its Relation To Electron Tomography For Materials Science Apoplications, Peter Moeck, P. Fraundorf
Physics Faculty Publications and Presentations
Aspects of transmission electron goniometry are discussed. Combined with high resolution phase contrast transmission electron microscopy (HRTEM) and atomic resolution scanning TEM (STEM) in the atomic number contrast (Z-STEM) or the phase contrast bright field mode, transmission electron goniometry offers the opportunity to develop dedicated methods for the crystallographic characterization of nanocrystals in three dimensions. The relationship between transmission electron goniometry and electron tomography for materials science applications is briefly discussed. Internet based java applets that facilitate the application of transmission electron goniometry for cubic crystals with calibrated tilt-rotation and double-tilt specimen holders/goniometers are mentioned. The so called cubic-minimalistic tilt …
Methods For High Resistivity Measurements Related To Spacecraft Charging, Jr Dennison, Jerilyn Brunson, Prasanna Swaminathan, Nelson Green, A Robb Frederickson
Methods For High Resistivity Measurements Related To Spacecraft Charging, Jr Dennison, Jerilyn Brunson, Prasanna Swaminathan, Nelson Green, A Robb Frederickson
Journal Articles
A key parameter in modeling differential spacecraft charging is the resistivity of insulating materials. This parameter determines how charge will accumulate and redistribute across the spacecraft, as well as the time scale for charge transport and dissipation. ASTM constant voltage methods are shown to provide inaccurate resistivity measurements for materials with resistivities greater than ~1017 Ω-cm or with long polarization decay times such as are found in many polymers. These data have been shown to often be inappropriate for spacecraft charging applications, and have been found to underestimate charging effects by one to four orders of magnitude for many …
Atomic And Electronic Structure Of Cofeb/Mgo Interface From First Principles, John D. Burton, Sitaram S. Jaswal, Evgeny Y. Tsymbal, O. G. Heinonen
Atomic And Electronic Structure Of Cofeb/Mgo Interface From First Principles, John D. Burton, Sitaram S. Jaswal, Evgeny Y. Tsymbal, O. G. Heinonen
Evgeny Tsymbal Publications
First-principles calculations of the atomic and electronic structure of crystalline CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJs) are performed to understand the effect of B on spin-dependent transport in these junctions. The authors find that it is energetically favorable for B atoms to reside at the crystalline CoFeB/MgO interface rather than remain in the bulk of the crystalline CoFeB electrode. The presence of B at the interfaces is detrimental to tunneling magnetoresistance (TMR) because it significantly suppresses the majority-channel conductance through states of symmetry. Preventing B segregation to the interfaces during annealing should result in an enhanced TMR in CoFeB/MgO/CoFeB MTJs.
Interlayer Exchange Coupling In Fe/Mgo/Fe Magnetic Tunnel Junctions, T. Katayama, S. Yuasa, Julian P. Velev, M. Ye. Zhuravlev, Sitaram S. Jaswal, Evgeny Y. Tsymbal
Interlayer Exchange Coupling In Fe/Mgo/Fe Magnetic Tunnel Junctions, T. Katayama, S. Yuasa, Julian P. Velev, M. Ye. Zhuravlev, Sitaram S. Jaswal, Evgeny Y. Tsymbal
Evgeny Tsymbal Publications
Interlayer exchange coupling (IEC) in fully epitaxial Fe/MgO/Fe (001) tunnel junctions with wedge-shaped MgO layers is measured at room temperature from the unidirectional shift of the Kerr hysteresis loop. It is found that the IEC is antiferromagnetic for small MgO thickness but changes sign at 0.8 nm. Ab initio calculations of IEC show that this behavior can be explained by the presence of O vacancies in the MgO barrier which makes IEC antiferromagnetic for thin barriers. With increasing MgO thickness the resonance contribution to IEC from localized defect states is reduced resulting in the ferromagnetic coupling typical for perfect MgO …
Magnetic Moment Softening And Domain Wall Resistance In Ni Nanowires, John D. Burton, Renat F. Sabirianov, Sitaram S. Jaswal, Evgeny Y. Tsymbal, O. N. Mryasov
Magnetic Moment Softening And Domain Wall Resistance In Ni Nanowires, John D. Burton, Renat F. Sabirianov, Sitaram S. Jaswal, Evgeny Y. Tsymbal, O. N. Mryasov
Evgeny Tsymbal Publications
We perform ab initio calculations of the electronic structure and conductance of atomic-size Ni nanowires with domain walls only a few atomic lattice constants wide. We show that the hybridization between noncollinear spin states leads to a reduction of the magnetic moments in the domain wall resulting in the enhancement of the domain wall resistance. Experimental studies of the magnetic moment softening may be feasible with modern techniques such as scanning tunneling spectroscopy.
Predicted Magnetoelectric Effect In Fe/Batio3 Multilayers: Ferroelectric Control Of Magnetism, Chun-Gang Duan, Sitaram S. Jaswal, Evgeny Y. Tsymbal
Predicted Magnetoelectric Effect In Fe/Batio3 Multilayers: Ferroelectric Control Of Magnetism, Chun-Gang Duan, Sitaram S. Jaswal, Evgeny Y. Tsymbal
Evgeny Tsymbal Publications
An unexplored physical mechanism which produces a magnetoelectric effect in ferroelectricferromagnetic multilayers is studied based on first-principles calculations. Its origin is a change in bonding at the ferroelectric-ferromagnet interface that alters the interface magnetization when the electric polarization reverses. Using Fe/BaTiO3 multilayers as a representative model, we show a sizable difference in magnetic moments of Fe and Ti atoms at the two interfaces dissimilar by the orientation of the local electric dipole moments. The predicted magnetoelectric effect opens a new direction to control magnetic properties of thin-film layered structures by electric fields.
Tunneling Across A Ferroelectric, Evgeny Y. Tsymbal, Hermann Kohlstedt
Tunneling Across A Ferroelectric, Evgeny Y. Tsymbal, Hermann Kohlstedt
Evgeny Tsymbal Publications
Spontaneously polarized materials through which electrons pass by tunneling may be used in novel electronic devices and may reveal new basic physics at the nanometer scale.
Holographic Recording In Nanoparticle-Doped Photopolymer, Izabela Naydenova, Hosam Sherif, Svetlana Mintova, Suzanne Martin, Vincent Toal
Holographic Recording In Nanoparticle-Doped Photopolymer, Izabela Naydenova, Hosam Sherif, Svetlana Mintova, Suzanne Martin, Vincent Toal
Conference Papers
A nanoparticle-doped acrylic photopolymer is characterised as a material for holographic recording. The influence of nanoparticles on the photopolymer dynamic range, dynamics of recording, temporal stability and mechanical stability in terms of shrinkage has been studied. The dynamics of recording and the temporal stability are investigated by real time monitoring of the build up of diffraction gratings of spatial frequencies of 200 to 2000 l/mm. The shrinkage has been characterised by recording slanted transmission gratings and observation of the change in the Bragg angle.