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
    Protons and other defects in Fe-doped KTaO3 (1992)
    Springer
    Applied physics 55 (1992), S. 324-331 
    Details
    ISSN: 1432-0630
    Keywords: 61.70−r ; 66.10.Ed ; 76.30.Fc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The properties of defects in Fe-doped KTaO3, both in the form of single crystals and polycrystalline ceramics, have been investigated for a wide range of Fe concentrations. The techniques employed included infrared (IR) absorption, electron paramagnetic resonance (EPR), and ac electrical conductivity together with complex-impedance analysis. Samples were pretreated (at 900° C) in water vapor to introduce protons which take the form of OH· O defects, and were also treated at various oxygen partial pressures. A calibration of the OH− IR absorption band was carried out with the aid of a deuterium nuclear-probe method. EPR showed cubic and axial Fe3+ spectra, but only the axial spectrum appeared for crystals with high Fe concentrations. Pre-dominantly proton conductivity was observed for samples treated in reducing atmospheres, and a proton-hopping activation energy of 0.73 eV was deduced. For samples treated in high oxygen pressures, however, hole conduction dominated. Evidence for proton interaction effects was also found, but the nature of the traps is not clear.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00324079
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Excited state absorption of Sm2+ in SrF2 and SrCl2 (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 6751-6756 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The excited state absorption spectrum of Sm2+ diluted as an impurity in the single crystal hosts SrF2 and SrCl2 has been observed. The absorption peaks associated with the 5D0(4f6) excited state were found to be displaced by approximately 3000 cm−1 from the absorption bands arising from the 7F0(4f6) ground state when the 5D0–7F0 energy was taken into account. The observed peak separation is ascribed to the 4f–5d exchange interaction. From the measured peak positions and band intensities, the exchange energy for the Sm2+ impurity in the two host crystals was determined to be about the same order of magnitude as that expected for the free ion. The implications of the properties of the excited state absorption bands for the performance of CaF2:Sm2+ and SrF2:Sm2+ lasers are considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.454420
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Electron paramagnetic resonance investigations of divalent cobalt in single crystals of perovskite (CaTiO3) (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 5117-5118 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The electron paramagnetic resonance (EPR) spectrum of Co2+ in CaTiO3 was observed at 9 GHz in the temperature range of 10–15 K. The results establish that Co2+ occupies four magnetically inequivalent sites in the orthorhombic CaTiO3 lattice. These sites become equivalent when the applied magnetic field is parallel to the so-called "pseudocubic'' b axis of the crystal. The magnetic axes in the plane perpendicular to the pseudocubic axis make an angle of ±28.5°±0.5° with the a and c axes of the host lattice. The site symmetry is qualitatively similar to that of the aliovalent ions Er3+ and Yb3+ in CaTiO3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.457604
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    EPR characterization of Er3+ and Yb3+ in single crystals of synthetic perovskite (CaTiO3) (1987)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 86 (1987), S. 5267-5272 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Synthetic perovskite (calcium titanate, CaTiO3) crystallizes in the orthorhombic structure with space group Pcmn (Z=4) and with lattice constants a=5.367, b=7.622, and c=5.425 A(ring). Single crystals of CaTiO3 doped with either Er3+ (4f11 electronic configuration) or Yb3+ (4f13 electronic configuration) were grown by means of a flux technique. A mixed KF–LiF flux and Pt crucibles were employed, and the CaTiO3 crystals were formed by spontaneous nucleation on slow cooling (1.0 °C/h) between 1250 and 875 °C. EPR spectra were observed for both Er3+ and Yb3+ at a frequency of ∼9 GHz and a temperature of ∼15 K. The EPR results establish that both Er3+ and Yb3+ occupy four magnetically inequivalent sites in the CaTiO3 lattice and that these sites become equivalent when the applied magnetic field is oriented parallel to the "pseudocubic'' b axis of the host synthetic perovskite crystal. The magnetic axes lying in the plane perpendicular to the b axis were found to make an angle with the a and c faces of the crystal that is equal to 21.0(5)° for Yb3+ and 11.5(5)° for Er3+. Isotopically enriched dopants were employed as an aid in analyzing the spectra, and the spin-Hamiltonian parameters have been determined for both rare-earth impurity ions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.452772
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    EPR and thermoluminescence investigations of Mn2+ in LuPO4, YPO4, and ScPO4 (1985)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 83 (1985), S. 6113-6120 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Divalent manganese has been incorporated in both single crystals and powders of the zircon-structure hosts LuPO4, YPO4, and ScPO4. The single-crystal specimens were grown by slowly cooling a Pb2P2O7 flux from 1360 °C, and finely divided powders of these materials were also prepared using a molten urea precipitation technique. Electron paramagnetic resonance studies have shown that tetragonal symmetry Mn2+ sites are present in both single crystals and powders of ScPO4 and LuPO4 but are not present in either YPO4 single crystals or powders. An orthorhombic symmetry spectrum was observed for Mn2+ in single crystals of all three hosts and in YPO4 powders. Orthorhombic spectra were not found in Mn2+ doped powders of ScPO4 and LuPO4. In the case of the orthorhombic-symmetry spectra, four sites were present in these tetragonal zircon-structure hosts. The sites were magnetically inequivalent but were equivalent in terms of the strength and symmetry of the crystalline electric field. The orientations of the orthorhombic-site principal axes relative to the crystallographic axes were determined in each case. The axial spin-Hamiltonian parameter b02 was found to be positive in the case of the tetragonal-symmetry sites and negative for the orthorhombic-symmetry spectra. Thermoluminescent properties of these materials were also investigated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.449603
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    The observation by EPR of trivalent hafnium in LuPO4, YPO4, and ScPO4 (1985)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 83 (1985), S. 2754-2758 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Recent EPR studies of the 4d1 configuration ion Zr3+ in the tetragonal-symmetry orthophosphate hosts LuPO4, YPO4, and ScPO4, have led to additional investigations of d1 configuration ions associated with unusual valence states of other elements. Single crystals of LuPO4, YPO4, and ScPO4 doped with hafnium were grown and the electron paramagnetic resonance (EPR) spectrum of the 5d1 ion Hf 3+ was observed in all three cases. EPR signals due to trivalent hafnium were only observed, however, when the doped samples were gamma irradiated at 77 K and maintained at 77 K during the EPR observations. Since there are two odd isotopes of hafnium with different nuclear spins and different natural abundances, identification of the spectrum of Hf 3+ was straightforward. Since Hf 3+ represents such an unusual valence for hafnium in the solid state, however, this identification was unequivocally verified by preparing crystals doped with isotopically enriched 179Hf. The spectroscopic splitting factors, g(parallel) and g⊥, and the parallel magnetic hyperfine constants A(parallel) of 177Hf and 179Hf were obtained for Hf 3+ in all three hosts. A determination of the hyperfine parameters with the applied magnetic field oriented in the perpendicular direction was not carried out due to quadrupole effects. As in the case of Zr3+, the observed electronic g values for Hf 3+ could not be accounted for by the standard second-order equations which included the spin-orbit-induced admixture of some other excited orbital levels of the d1 configuration into the ground orbital level. The ratio of the nuclear magnetic moments 177μ/179μ, was determined to be 1.2361(4) and 1.2362(3) for hafnium in ScPO4 and LuPO4, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.449225
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    EPR observations of trivalent titanium in orthophosphate single crystals (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 1-6 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The ground state spectroscopic properties of the 3d1 electronic configuration ion Ti3+ have been investigated using EPR spectroscopy. Trivalent titanium was incorporated as a dilute impurity in single crystals of the tetragonal, zircon-structure hosts ScPO4, YPO4, and LuPO4. The EPR spectrum of Ti3+ was observed in the as-grown orthophosphate crystals, and low temperature irradiations were not required to produce the trivalent state. The EPR results show that Ti3+ occupies a substitutional cation site in the host orthophosphate single crystals. Axial spin-Hamiltonian parameters were determined at 77 K, and these results are compared to those obtained previously for the 4d1 and 5d1 configuration ions Zr3+ and Hf 3+ in the same host crystals. Titanium-doped orthophosphate crystals containing isotopically enriched 47Ti or 49Ti were also grown and employed in determinations of the hyperfine parameters. The g-values observed here for Ti3+, and determined previously for Zr3+ and Hf 3+ are not accounted for by the published second-order expressions indicating that additional coupling mechanisms are operative.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451638
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Study of epitaxial platinum thin films grown by metalorganic chemical vapor deposition (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 3735-3740 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The metalorganic chemical vapor deposition technique has been successfully applied to the growth of epitaxial platinum thin films on (100) surfaces of single-crystal potassium tantalate (KTaO3) and strontium titanate (SrTiO3). Platinum thin films grown on KTaO3 (100) at a rate of 70 nm/h showed strong Rutherford backscattering spectroscopy (RBS)/channeling effects with a χmin of 4%. In-plane φ and θ-2θ scan x-ray diffraction analysis demonstrated the three-dimensional epitaxial alignment of the platinum film with the KTaO3 substrate. Transmission electron micrographs viewed in cross section provided additional information regarding the nature of the epitaxial Pt-KTaO3 interface. The room-temperature resistivity of a 60-nm-thick Pt film on KTaO3 (100) was 12.0 μΩ cm. X-ray diffraction and pole-figure analysis showed that in the case of Pt films deposited on either fused quartz or Si (100) surfaces, the resulting films were polycrystalline and were fully textured with 〈111(approximately-greater-than) orientations perpendicular to the substrate surfaces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352293
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    A transient liquid-like phase in the displacement cascades of zircon, hafnon and thorite (1998)
    [s.l.] : Macmillan Magazines Ltd.
    Nature 395 (1998), S. 56-58 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The study of radiation effects in solids is important for the development of ‘radiation-resistant’ materials for fission-reactor applications. The effects of heavy-ion irradiation in the isostructural orthosilicates zircon (ZrSiO4), hafnon (HfSiO4) and thorite ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/25698
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Excited state absorption and fluorescence line narrowing studies of Cm3+ in LuPO4 (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 105 (1996), S. 2539-2546 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Laser selective excitation, fluorescence line narrowing, and excited state absorption techniques have been used to investigate the electronic-energy-level structure of the 5f7 ion Cm3+ in the host crystal LuPO4. Crystal-field levels have been determined up to 35 700 cm−1 for the principal D2d symmetry site. Eighty levels have been assigned and fitted to a parametric Hamiltonian with an rms deviation of 28.4 cm−1. Inhomogeneous broadening of the electronic transitions and the small 9.5 cm−1 splitting of the nominally 8S7/2 ground multiplet are responsible for satellite lines reported previously. Time resolved fluorescence line narrowing was used to observe energy transfer between different subsites of the intrinsic Cm3+ center. It was found that electric-dipole interactions mediate this energy transfer. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.472118
    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...