ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Infrared study of OH− defects in KTiOPO4 crystals (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 5371-5380 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Variations in the concentrations and distributions of the OH− defects present in flux and hydrothermal KTiOPO4 (KTP) crystals, measured by infrared spectroscopy of single crystals, are attributed to differences in the growth environments and other nonhydrogenic defects present in the crystals. The concentrations of OH− have been estimated from the infrared data to be approximately 400 ppma (parts per million atomic) (3.0×1019 cm−3) in the flux crystals, 1100–1500 ppma (0.74–1.1×1020 cm−3) in the high-temperature hydrothermal and 600 ppma (4.3×1019 cm−3) in the low-temperature hydrothermal crystals. A 3566 cm−1 peak and a 3575 cm−1 band are observed in all crystals. The integrated intensity of the OH− absorption band at 3566 cm−1 increases at the expense of the 3575 cm−1 band at higher temperatures in the high-temperature hydrothermal crystals. Several OH− peaks (3490, 3455, 3428, 3420, and 3333 cm−1), which have strongly temperature-dependent linewidths, are present in the hydrothermally grown KTP crystals. The temperature dependencies of their peak frequencies and widths are consistent with the presence of mobile protons in the lattice. The protons located in the 3490 and 3428 cm−1 sites are believed to contribute to the ionic conductivity of the high-conductivity high-temperature hydrothermal crystals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351976
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Numerical analysis of charge transport in semi-insulating GaAs with two contacts (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 3611-3618 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The dc, steady state charge transport in 200-μm-thick semi-insulating GaAs samples with two large whole area metal contacts is calculated numerically. The material is assumed to have shallow donors and an excess of deep acceptors. The distributions of the space charge density and of electron and hole conductivities are calculated for different electron and hole-supplying contacts with different bias voltages. It is found that the contact which injects majority carriers into the semiconductor due to the voltage bias determines the distribution of the space charge density in a greater volume of the sample than the other contact. Consequently, this contact is decisive for the space distribution of the electric field and the shape of the current–voltage (I–V) characteristic. Comparison is made with experimental observations of the I–V characteristics of one of our detector of particles. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.361415
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Some properties of 2π Néel walls and Néel points in the XY model : 35 th annual conference on magnetism and magnetic materials (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 5959-5961 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The properties of two types of topological defects in the 2D classical XY model, Néel lines and Néel points, have been investigated via numerical simulation. The effect of a symmetry-breaking magnetic field has been considered. For cyclic boundary conditions a uniform array of line defects can be stabilized. Along a line defect, point defects can be introduced as spatial changes of chirality of the wall. These point defects consist of pairs of bound vortices of the same sign. When several such point defects are introduced on a given line defect, they also tend toward uniform spacing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.347829
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Critical behavior in the two-impurity Kondo problem (abstract) (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 5221-5221 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The antiferromagnetic two-impurity Kondo problem, involving two magnetic moments coupled antiferromagnetically to each other and also to a band of itinerant electrons, has been found to exhibit nontrivial behavior.1 We show analytically2 that the presence of a type of particle-hole symmetry guarantees a nonanalyticity in the ground-state energy as the antiferromagnetic RKKY coupling is varied relative to the Kondo temperature. This symmetry is not present in the generic antiferromagnetic two-impurity model. Previous work on the symmetric model1 has shown that the nonanalyticity is a second-order T=0 phase transition with diverging specific heat coefficient and staggered susceptibility. We have studied the effect of breaking the symmetry via an analytic large-N expansion and via Wilson's numerical renormalization group technique. The analytic work suggests that there may be no transition if the symmetry is broken. The preliminary numerical work suggests either that the transition survives, or that there is a well-defined crossover signalled by an order of magnitude or more enhancement of the specific heat coefficient. Further analytic and numerical work is in progress to resolve the dilemma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.344616
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Approximation of turbulent conditional averages by stochastic estimation (1989)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 1 (1989), S. 992-998 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Conditional averages of turbulent flow quantities can be approximated in terms of unconditional correlation data by means of stochastic estimation. The validity and accuracy of this procedure are investigated by comparing stochastic estimates to conditional averages measured in four turbulent flows: grid turbulence, the axisymmetric shear layer of a round jet, a plane shear layer, and pipe flow. Comparisons are made for quantities that are separated from the conditional data in time or space, and for turbulent pressures, as well as turbulent velocities. In each case, the linear estimate accurately represents large scale structure. Nonlinear quadratic estimation shows little improvement over linear estimation, because the second-order terms are small for probable values of the turbulent fluctuations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.857411
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Transient transport experiments in the current-drive experiment upgrade spherical torus (2002)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 9 (2002), S. 480-487 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electron transport has been measured in the Current-Drive Experiment Upgrade (CDX-U) (T. Jones, Ph.D. thesis, Princeton University, 1995) using two separate perturbative techniques. Sawteeth at the q=1 radius (r/a∼0.15) induced outward-propagating heat pulses, providing time-of-flight information leading to a determination of χe as a function of radius. Gas modulation at the plasma edge introduced inward-propagating cold pulses, providing a complementary time-of-flight based χe profile measurement. This work represents the first localized measurement of χe in a spherical torus. Core (r/a〈1/3) χe values from the sawtooth study are 1–2 m2/s, and from the gas modulation study are 1–6 m2/s, increasing by an order of magnitude or more outside of the core region. Furthermore, the χe profile exhibits a sharp transition near r/a=1/3. Spectral and profile analyses of the soft x-rays, scanning interferometer, and edge probe data show no evidence of a significant magnetic island causing the high χe region. Comparisons are performed to several theoretical models, with measured χe(approximate)5–10× neoclassical estimates in the core. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1428557
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Enhancement of mode-converted electron Bernstein wave emission during National Spherical Torus Experiment H-mode plasmas (2002)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 9 (2002), S. 167-170 
    Details
    ISSN: 1089-7674
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A sudden, threefold increase in emission from fundamental electrostatic electron Bernstein waves (EBW) which mode convert and tunnel to the electromagnetic X-mode has been observed during high energy and particle confinement (H-mode) transitions in the National Spherical Torus Experiment (NSTX) plasma [M. Ono, S. Kaye, M. Peng et al., in Proceedings of the 17th IAEA Fusion Energy Conference (IAEA, Vienna, Austria, 1999), Vol. 3, p. 1135]. The mode-converted EBW emission viewed normal to the magnetic field on the plasma midplane increases when the density profile steepens in the vicinity of the mode conversion layer, which is located in the plasma scrape off. The measured conversion efficiency during the H-mode is consistent with the calculated EBW to X-mode conversion efficiency derived using edge density data. Calculations indicate that there may also be a small residual contribution to the measured X-mode electromagnetic radiation from polarization-scrambled, O-mode emission, converted from EBWs. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1423336
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Measurement of the electrical properties of electromigration specimens (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 4676-4680 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A description is given of the design, implementation, and performance of a circuit to measure the electrical properties of resistive specimens of about 10 Ω such as are used in electromigration studies. The ac bridge can measure the changes in resistance, second-harmonic amplitude, second-harmonic phase shift, thermal noise, and excess (1/f) electrical noise. All the parameters can be monitored simultaneously and continuously. The performance is comparable with that of systems designed to measure each of the quantities only. The special features are that it is an autobalance bridge so that changes in the measured quantities are recorded by the feedback signal, the spectrum analyzer is not overloaded, and the recovery of the noise signal is performed by software. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145306
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Towards metallic magnetic memory: How to interpret experimental results on magnetic switching induced by spin-polarized currents (2001)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 6793-6795 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In the field of magnetic memory the giant magnetoresistance effect provides a convenient way to read out the state of a spin-valve type device by passing a small current through it. It is now debated whether passing a large current through such a device could reliably switch its magnetic state between parallel and antiparallel configurations thus turning a spin valve into a complete read–write memory cell. Experiments with current induced switching were done by several groups, but their interpretation is not straightforward due to complicated interplay between the current-induced torques and those induced by anisotropy. We propose here an experimental setup where an exact solution for the switching behavior can be found in the framework of Slonczweski's approach. Comparison with experiment would be especially interesting since alternative approaches are discussed in the literature. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1362642
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Magnetic impurity in a superconductor: Local phase transitions and finite size effects (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 87 (2000), S. 5561-5563 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The influence of a single magnetic impurity on an s-wave superconductor is investigated by solving the Bogoliubov-De Genne equations with the impurity modeled by a spin-dependent square potential well of radius a and strength J. Unlike the one with a δ-function potential, our model shows multiple phase transitions with increase of J or a, which manifest themselves through a change of the nature of impurity bound states. By considering a finite size superconducting host (impurity on a superconducting grain) we suggest a way of observing the transitions in experiment. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.373404
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...