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
    Hot carrier relaxation processes and nonequilibrium phonon effect in multiple quantum well structures
    Amsterdam : Elsevier
    Journal of Luminescence 46 (1990), S. 137-145 
    Details
    ISSN: 0022-2313
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0022-2313(90)90014-3
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Nuclear dynamics in the vicinity of the crossing seam: Theory and application to vibrational spectrum of H3 (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 112 (2000), S. 2121-2127 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Based on the equivalence of the gauge transformations for the nuclear and electronic wave functions, the physical meaning of the geometric phase effect has been disclosed for a two coupled-state system. It is found that the geometric phase A(R) is defined by the argument of the complex electronic vector state in the complex plane spanned by the two real-valued electronic components. Such an angle is identical (up to a constant) to the mixing angle γ(R). Novel generalized Born–Oppenheimer equations for the two coupled-state problem in the vicinity of the crossing seam have been derived, and numerical calculations of vibrational spectra done for H3. The results demonstrate significant differences in relation to those obtained from the assumption that A(R)=φ/2. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.480823
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Compositional evolution and magnetic properties of nanocrystalline Fe81.5Cu0.5Mo0.5P12C3Si2.5 (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 3972-3976 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The amorphous alloy Fe81.5P12C3Cu0.5Mo0.5Si2.5 has been prepared and the crystallized alloy exhibits an ultrafine structure with a grain size of about 20 nm and excellent soft magnetic properties. The coercivity and the core loss as low as 6.7 A/m, 0.26 W/kg, respectively, and the maximum permeability as high as 10.2×104 at an optimal annealing temperature of about 360 °C were obtained. By means of x-ray diffraction, transmission electron microscope, and Mössbauer spectroscopy measurements, microstructures of the alloy were investigated as a function of the annealing temperature. The primary crystallization produces ultrafine grains of α-Fe(Si) solid solution with a grain size of about 20 nm precipitated in the residual amorphous matrix. The Si in the α phase was estimated near to be completely disorder ranged and the Si concentration was determined to be about 2%–5%. The Fe3P phase appears in the residual amorphous phase upon annealing at 420 °C. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363355
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Disordered oxygen octahedral rotations and glasslike polarization characteristics in rhombohedral lead zirconate titanate (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 1919-1921 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Disordered oxygen octahedral rotations have been observed in the low-temperature rhombohedral ferroelectric state in the Pb(Zr1−xTix)O3 crystalline solution. The development of disordered oxygen octahedral rotations within the ferroelectric state was found to result in the interruption of long-range polar order and the development of fluctuation effects. Dielectric relaxation was observed below ∼160 °C for Pb(Zr0.65Ti0.35)O3. In addition, double-looplike characteristics were observed in the polarization electric-field (P–E) response in the same temperature range. The results clearly reveal the nature of the coupling between the polarization and oxygen octahedral rotations in a perovskite ferroelectric structure. It was also shown that a small amount of La doping can enhance the degree of ordering of the octahedral tilted state. The enhancement of the ordering was verified by an intensity increase of the 1/2〈111〉 superlattice reflections in the selected area electron-diffraction pattern. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363009
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Influence of lower-valent A-site modifications on the structure-property relations of lead zirconate titanate (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 5866-5874 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Studies of the structure-property relationships have been performed for lead zirconate titanate as a function of concentration of a lower-valent A-site substitution. Investigations focused on the system (Pb1−yKy)(Zr0.65Ti0.35)O3−y/2 for 0〈y〈0.20. These studies revealed modest changes in the dielectric response with increasing K1+ concentration. However, no evidence of relaxor ferroelectric characteristics was found. Transmission electron microscopy (TEM) studies were also performed. These investigations revealed strong changes in the ferroelectric domain structures with moderate increases in K1+ concentration. For K content (approximately-greater-than)4%, fine ferroelectric domains were found, which possessed a strong degree of wavy character. Increasing K1+ concentration resulted in further decreases in domain size. Sawyer–Tower polarization studies then demonstrated a strong reduction in the switchable polarization with increasing K1+ concentration, indicating that the polarization becomes pinned. Hot-stage TEM investigations were then performed. These studies revealed evidence for a pinning of the polarization into fine wavy domains at temperatures significantly below that of the ferroelectric transformation. These results are then compared to recent investigations of the influence of La3+ on the same base composition. We believe that the differences between lower- (K1+) and higher- (La3+) valent A-site modifications can be explained on the basis of the influence of quenched (which become mobile on heating in the ferroelectric phase) versus randomly quenched (above the ferroelectric transformation) defect complexes on the evolution of polar order. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363580
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Optical study of heterointerface configuration in narrow GaAs/AlGaAs single quantum wells prepared with growth interruption (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 1073-1077 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photoluminescence and time-resolved photoluminescence were used to study the heterointerface configuration in GaAs/AlGaAs quantum wells grown by molecular-beam epitaxy with growth interruption. Photoluminescence spectra of the growth-interrupted sample are characterized by multiplet structures, with energy separation corresponding to a 0.8 monolayer difference in well width, rather than 1 monolayer as expected from the "atomically smooth island'' picture. By analyzing the thermal transfer process of the photogenerated carriers and luminescence decay process, we further exploit the exciton localization at the interface microroughness superimposed on the extended growth islands. The lateral size of the microroughness in our sample was estimated to be 5 nm, less than the exciton diameter of 15 nm. Our results strongly support the bimodal roughness model proposed by Warwick et al. [Appl. Phys. Lett. 56, 2666 (1990)]. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360896
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Observation of a near-static condensation of polarization fluctuations in strontium barium niobate (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 1677-1682 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The dielectric response characteristics of SrxBa1−xNb2O6 for 0.50〈x〈0.75 have been investigated as a function of temperature. Cold-stage transmission electron microscopy studies were performed for comparative purposes. An anomalous relaxation of tan δ was observed in the temperature range of −100 to −50 °C, which was previously unreported. Near this temperature range the dielectric constant was also found to become frequency independent. These results are interpreted in terms of a near-static condensation of polarization fluctuations, reflecting the trailing edge of the relaxation time distribution approaching long time periods. Selected-area electron-diffraction investigations revealed an incommensurate reflection along the 〈110〉 which exhibits diffuse scattering. Near the temperature of the static condensation of polarization fluctuations, the degree of diffuse scattering was found to decrease significantly. In addition, bright-field imaging revealed a significant increase in the size of needlelike nanosized ferroelectric regions in this temperature range. It is proposed that the near-static condensation of polarization fluctuations is driven by small structural changes in the channels of the tungsten bronze structure. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.358857
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Phase stability and transformations in pure and lanthanum modified lead zirconate ceramics (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 5086-5094 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Lanthanum modified lead zirconate with La to 8 at. % were prepared using mixed oxide method and followed by hot press sintering. The basic characterization included: dielectric spectroscopy, Sawyer–Tower polarization measurements, and temperature dependent selected area electron diffraction techniques. An intermediate rhombohedral ferroelectric phase (FER), characterized by square hysteresis loops, was found to exist in lead zirconate below the dielectric maximum. Strong 1/2{110} superlattice reflections associated with M-type oxygen octahedral rotation is found in the intermediate rhombohedral ferroelectric state. In addition, 1/x{110} incommensurate reflections were observed within a narrow temperature range between the FER phase and the low-temperature orthorhombic antiferroelectric state. With increasing La content, the temperature stability range of the incommensurate antiferroelectric phase was increased, at the expense of the FER phase. Incommensuration is suggested to result from a competition between "broken'' dipolar and antiferroelectric sublattice interactions. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359317
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Normal to relaxor ferroelectric transformations in lanthanum-modified tetragonal-structured lead zirconate titanate ceramics (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 1021-1026 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Lanthanum modified lead zirconate titanate (PLZT) ceramics near a crossover between normal and relaxor ferroelectric states for Zr/Ti ratios of 40/60, 20/80, and 0/100 were investigated by dielectric spectroscopy, Sawyer–Tower polarization techniques and transmission electron microscopy. It was found possible to induce a relaxor state in each of these tetragonal PLZT compositional sequences with increasing La content. The transformation between normal and relaxor-like behaviors was found to be associated with a domain evolution from normal micron-sized domains, to tweed-like subdomain structures, and finally to polar nanodomains. A spontaneous relaxor to normal transformation was found near a critical La content in each compositional sequence. Temperature dependent polarization studies revealed a field-induced relaxor to normal ferroelectric transition at temperatures above that of the spontaneous transformation. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360889
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Energy relaxation processes of hot quasi-two-dimensional excitons in very thin GaAs/AlGaAs quantum wells by exciton–acoustic-phonon interaction (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 424-426 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The rising time of the excitonic luminescence in GaAs/AlGaAs quantum wells is studied as a function of the well width. For well thickness below approximately 20 A(ring), we find an increase of rising time with decreasing well width. We explain the dependence of the rising time on well width in very thin quantum wells by the slow-down energy relaxation and/or exciton migration processes due to the decrease of the scattering rate of the exciton–acoustic-phonon interaction. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360847
    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...