Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Engineering (11)
- Materials Science and Engineering (8)
- Applied Mathematics (4)
- Chemistry (4)
- Materials Chemistry (4)
-
- Optics (4)
- Other Applied Mathematics (4)
- Physical Chemistry (4)
- Electrical and Computer Engineering (2)
- Electromagnetics and Photonics (2)
- Biological and Chemical Physics (1)
- Computer Sciences (1)
- Engineering Physics (1)
- Nanoscience and Nanotechnology (1)
- Numerical Analysis and Scientific Computing (1)
- Quantum Physics (1)
- Institution
- Keyword
-
- Condensed matter (2)
- Aluminum (1)
- Angles (Geometry) -- Mesurement (1)
- Copper (1)
- Crystalling alloys (1)
-
- Crystals -- Defects (1)
- Curie temperature (1)
- Electric domain walls (1)
- Ferroelasticity (1)
- Holography (1)
- Inorganic nanoparticles (1)
- Lead compounds (1)
- Mesoscale and nanoscale physics (1)
- Nanostructured materials (1)
- Nanotechnology (1)
- Nucleation (1)
- Photopolymers (1)
- Piezoceramics (1)
- Quantum physics (1)
- Shrinkage of photopolymers (1)
- Stacking faults (1)
- Superconductivity (1)
- Texture (1)
- Transmission electron microscopes (1)
- X-ray diffraction (1)
- Publication
- Publication Type
- File Type
Articles 1 - 26 of 26
Full-Text Articles in Condensed Matter Physics
Harmonic Detection Of Resonance In Micro- And Nano- Cantilevers, Jay Gaillard
Harmonic Detection Of Resonance In Micro- And Nano- Cantilevers, Jay Gaillard
All Dissertations
Over the past decade there has been an explosion in the study of cantilevered beams on the micron and submicron dimension. The applications and research that involve these structures include state-of-the-art electronic components, sensors, and more recently, studies aimed at elucidating the mechanical properties of cantilevered carbon nanotubes and semiconducting nanowires. In nanoelectro-mechanical systems (NEMS), it is desirable to develop a capacitive readout method involving only two electrodes that are fully compliant with standard CMOS technology. However, the main drawback with this method is the ability to detect resonance in the presence of parasitic capacitance, which is due to the …
Assembly And Modification Of A Hyperthermal And Low Energy Ion Beamline For Detecting Electron-Hole Pair Production In Schottky Diodes, Matthew Ray
All Theses
A hyperthermal and low energy ion beamline to measure electron-hole pair production due to ion bombardment of Schottky diodes has been modified and assembled.
A brief overview of the instrument is given and the reason for operating the ion beamline in the hyperthermal and low energy regime is discussed. The capabilities of the ion beamline are unique and provide the means to measure quantities that offer insight into various energy exchange mechanisms that occur at surfaces. Combined with the ability to accept Schottky diode samples, the beamline is capable of measuring both charge transfer and electron-hole pair production caused by …
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.
Posterminaries: After Nabarro, Alexander H. King
Posterminaries: After Nabarro, Alexander H. King
Alexander H. King
With the passing of Frank Nabarro in July of this year, we have lost one of the founding fathers of materials science. His name appears in many of the textbooks from which we train our students today, and also on the spines of several volumes on dislocation theory, including his classic monograph on the subject. He rightly stands among the gods of our field. Ninety years old at his death, he was a sprightly dancer at the frontiers of knowledge, right up to the end.
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.
Comment On “Structural Stability Of Complex Hydrides: Libh4 Revisited”, Duane D. Johnson, Nikolai A. Zarkevich
Comment On “Structural Stability Of Complex Hydrides: Libh4 Revisited”, Duane D. Johnson, Nikolai A. Zarkevich
Duane D. Johnson
A Comment on the Letter by Zbigniew Łodziana and Tejs Vegge, Phys. Rev. Lett. 93, 145501 (2004).
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 …
Posterminaries: The Scales Of Judgement, Alexander H. King
Posterminaries: The Scales Of Judgement, Alexander H. King
Alexander H. King
Materials scientists are generally well-versed in physics, and physics, above all, is a science of measurements. The first instinct of a physicist is to parse a problem in terms of its measurables in the dimensions of mass, length, and time, and it is the shifting of attention down the scale of length that particularly characterizes our present times as the Nano Age.
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.
Posterminaries: Plain Text, Alexander H. King
Posterminaries: Plain Text, Alexander H. King
Alexander H. King
You just can’t win an argument with an English professor.
Thermal Effects On Domain Orientation Of Tetragonal Piezoelectrics Studied By In Situ X-Ray Diffraction, Wonyoung Chang, Alexander H. King, Keith J. Bowman
Thermal Effects On Domain Orientation Of Tetragonal Piezoelectrics Studied By In Situ X-Ray Diffraction, Wonyoung Chang, Alexander H. King, Keith J. Bowman
Alexander H. King
Thermal effects on domain orientation in tetragonal lead zirconate titanate (PZT) and lead titanate (PT) have been investigated by using in situ x-ray diffraction with an area detector. In the case of a soft PZT, it is found that the texture parameter called multiples of a random distribution (MRD) initially increases with temperature up to approximately 100 °C and then falls to unity at temperatures approaching the Curie temperature, whereas the MRD of hard PZT and PT initially undergoes a smaller increase or no change. The relationship between the mechanical strain energy and domain wall mobility with temperature is discussed.
Recycling Krylov Subspaces For Sequences Of Linear Systems, Michael L. Parks, Eric De Sturler, Greg Mackey, Duane D. Johnson, Spandan Maiti
Recycling Krylov Subspaces For Sequences Of Linear Systems, Michael L. Parks, Eric De Sturler, Greg Mackey, Duane D. Johnson, Spandan Maiti
Duane D. Johnson
Many problems in science and engineering require the solution of a long sequence of slowly changing linear systems. We propose and analyze two methods that significantly reduce the total number of matrix‐vector products required to solve all systems. We consider the general case where both the matrix and right‐hand side change, and we make no assumptions regarding the change in the right‐hand sides. Furthermore, we consider general nonsingular matrices, and we do not assume that all matrices are pairwise close or that the sequence of matrices converges to a particular matrix. Our methods work well under these general assumptions, and …
Solute/Defect-Mediated Pathway For Rapid Nanoprecipitation In Solid Solutions: Γ Surface Analysis In Fcc Al-Ag, Daniel Finkenstadt, Duane D. Johnson
Solute/Defect-Mediated Pathway For Rapid Nanoprecipitation In Solid Solutions: Γ Surface Analysis In Fcc Al-Ag, Daniel Finkenstadt, Duane D. Johnson
Duane D. Johnson
In face-centered-cubic (fcc) Al, stacking fault energy (SFE) is high at ca. 150mJ/m2, inhibiting stacking fault (SF) formation and dislocation motion. Yet Ag-rich hcp precipitates form rapidly in Al-rich fcc Al-Ag, even as the energy difference ΔEhcp−fcc between hcp and fcc homogeneous solid solution increases with Ag content. Using electronic density functional theory methods, we calculate the SFE γSF versus distance of Ag (111) planes from intrinsic (isf), extrinsic (esf) and twin (tsf) SFs. We find that an inhomogeneous distribution of Ag solute segregated in layers adjacent to SFs leads to favorable SFE, a manifestation of the well-known Suzuki effect. …
Generalized Planar Fault Energies And Twinning In Cu–Al Alloys, S. Kibey, J. B. Liu, Duane D. Johnson, H. Sehitoglu
Generalized Planar Fault Energies And Twinning In Cu–Al Alloys, S. Kibey, J. B. Liu, Duane D. Johnson, H. Sehitoglu
Duane D. Johnson
We report ab initio density functional theory calculations of generalized planar fault energies of fcc Cu–xAl (x=0, 5.0, and 8.3at.%) alloys. We investigate the effects of substitutional solute Al on the unstable intrinsic γus and twin γutstacking faultenergies (SFEs). Our results reveal an increased tendency of Cu–Al to deform preferentially by twinning with increasing Al content, consistent with experiment. We attribute this mechanical behavior to appreciable lowering of the twinning barrier γut, along with the stable intrinsic and twin SFEs.
Optical Characterization Of Ferromagnetic Heterostructure *Interfaces And Thin Films, Haibin Zhao
Optical Characterization Of Ferromagnetic Heterostructure *Interfaces And Thin Films, Haibin Zhao
Dissertations, Theses, and Masters Projects
This thesis presents optical characterizations of interfaces in ferromagnetic heterostructures and thin films used for spin polarized electronic devices. In these experiments, femtosecond laser spectroscopies are exploited to investigate the interface magnetization reversal, spin precession, and band offset, which are crucial in determining the performances of spintronic devices.;First, magnetization-induced second-harmonic-generation (MSHG) is applied to study interface magnetism in a hybrid structure containing a noncentrosymmetric semiconductor---Fe/AlGaAs. The reversal process of Fe interface layer magnetization is compared with the bulk magnetization reversal. In Fe/AlGaAs (001), the interface magnetization is found to be decoupled from the bulk magnetization based on the different switching …
Ultrafast Laser Spectroscopy Of Half -Metallic Chromium Dioxide, Hailong Huang
Ultrafast Laser Spectroscopy Of Half -Metallic Chromium Dioxide, Hailong Huang
Dissertations, Theses, and Masters Projects
This thesis presents ultrafast laser pump-probe differential transmission experiments on epitaxial CrO2 (110). The experiments were conducted at the wavelengths of 600 nm, 800 nm and 1200 nm, corresponding to the transition energies of 2 eV, 1.5 eV and 1 eV respectively. The wavelength dependent results, comparing with linear optical absorption, revealed the electronic structure of the material. The experimental results also showed polarization dependence of the probe beams. This is attributed to the electronic orbital anisotropy.;Temperature dependence was observed in the pump-probe experiments. The ultrafast transmission data show similar temperature dependence as ultrafast MOKE (Magneto-Optical Kerr Effect) data. A …
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.
Carbon Nanosheets And Carbon Nanotubes By Rf Pecvd, Mingyao Zhu
Carbon Nanosheets And Carbon Nanotubes By Rf Pecvd, Mingyao Zhu
Dissertations, Theses, and Masters Projects
A planar antenna RF plasma enhanced chemical vapor deposition apparatus was built for carbon nanostructure syntheses. When operated in inductive and capacitive plasma discharging modes, two carbon nanostructures, carbon nanotube (CNT) and carbon nanosheet (CNS), were synthesized, respectively.;A nanosphere lithography method was developed and used to prepare catalyst patterns for CNT growth. Using capacitively coupled C2H2/NH 3 plasma, randomly oriented CNT were synthesized on Ni dot patterned Si substrates. Aligned CNT arrays were grown on SiO2 coated Si substrates, using both C2H2/NH3 and CH 4/H2 capacitive plasmas.;When operated in inductive coupling mode, CNS were successfully deposited on a variety of …
Internal Magnetic Field Distribution Of A Type Ii High Tc Superconductor With Non-Conducting Inclusions, Yuxin Dai
Dissertations, Theses, and Masters Projects
The internal magnetic field distributions for a type II superconductor (a single crystal YBa2Cu3O7-delta ) with large normal inclusions (YBa2Cu3O 7-delta) are studied. A model based on the London Equations has been successfully developed and applied to the interpretation of the pSR data on this system. In our model, these inclusions are assumed to be cylindrical in shape and infinite in length. Therefore, this model should be especially appropriate for the prediction of field distributions in single crystal superconductors in which columnar defects have been purposely introduced to enhance pinning.;muSR experiments on a large single-crystal sample of YBa2C u3O7-delta with …
Time-Resolved Magneto-Optical Imaging Of Superconducting Ybco Thin Films In The High-Frequency Ac Current Regime, Alexander Frey
Time-Resolved Magneto-Optical Imaging Of Superconducting Ybco Thin Films In The High-Frequency Ac Current Regime, Alexander Frey
Dissertations, Theses, and Masters Projects
No abstract provided.
Static And Ultrafast Moke Studies Of Exchange -Biased Cobalt Systems, Keoki A. Seu
Static And Ultrafast Moke Studies Of Exchange -Biased Cobalt Systems, Keoki A. Seu
Dissertations, Theses, and Masters Projects
We have studied the exchange bias interaction in metal bilayers IrMn/Co and FeMn/Co using the static and ultrafast pump-probe Kerr effects. Experiments conducted on wedged Co samples show that the exchange bias interaction is sensitive to the buffer layers grown beneath it when the antiferromagnetic layer is FeMn. The exchange bias strength, as measured by the shift in the magnetic hysteresis loop, follows a 1/tFM dependence as reported in the literature. The time-domain pump-probe experiments reveal coherent magnetization oscillations, whose frequencies are comparable to those measured by frequency-domain FMR measurements, and they fit well to FMR equations for the frequency. …
Jet-Based Methods To Print Living Cells, Bradley Ringeisen, Christina Othon, Jason Barron, H Young, Barry Spargo
Jet-Based Methods To Print Living Cells, Bradley Ringeisen, Christina Othon, Jason Barron, H Young, Barry Spargo
Christina M Othon
Cell printing has been popularized over the past few years as a revolutionary advance in tissue engineering has potentially enabled heterogeneous 3-D scaffolds to be built cell-by-cell. This review article summarizes the state-of-the-art cell printing techniques that utilize fluid jetting phenomena to deposit 2- and 3-D patterns of living eukaryotic cells. There are four distinct categories of jetbased approaches to printing cells. Laser guidance direct write (LG DW) was the first reported technique to print viable cells by forming patterns of embryonic-chick spinal-cord cells on a glass slide (1999). Shortly after this, modified laser-induced forward transfer techniques (LIFT) and modified …