Library

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
Filter
  • 2000-2004  (2)
  • 1970-1974  (2)
  • 1
    Electronic Resource
    Electronic Resource
    Etude des phases haute température de NaNb3 et des correlations qui les caracterisent (1974)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 30 (1974), S. 423-430 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: From the study of X-ray diffuse scattering diagrams, it has been shown that the diffuse scattering located along three equivalent reciprocal rods (100) in the cubic phase disappears successively at 641, 575 and 520°C. The interpretation is given in terms of planar local order.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0567739474000921
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    X-ray diffuse scattering from NaNbO3 as a function of temperature (1971)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 27 (1971), S. 414-420 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: A qualitative description of the X-ray diffuse scattering from NaNbO3 single crystals as a function of temperature up to 800°C is given. Two types of distinct diffuse scattering where observed in {100} reciprocal planes and on (100) reciprocal axes. While the diffuse scattering in reciprocal planes shows no critical behaviour at the different phase transitions and can be attributed to a `linear disorder' similar to that suggested earlier for KNbO3, the diffuse scattering on reciprocal axes is critical in the vicinity of the 641°C phase transition. The atomic displacements involved with the linear disorder that persists up to 800°C are attributed to the niobium atoms; the critical planar disorder in the cubic phase is attributed to rotations of oxygen octahedra similar to those suggested for SrTiO3 and KMnF3. Both types of disorder exist in the cubic paraelectric phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0567739471000950
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    The Al-Pd-Mn quasicrystalline approximant -phase revisited (2002)
    Springer
    The European physical journal 29 (2002), S. 51-59 
    Details
    ISSN: 1434-6036
    Keywords: PACS. 61.44.Br Quasicrystal – 61.10.-i X-ray diffraction and scattering – 61.10Nz Single crystal and powder diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: A detailed investigation of the Fourier space of several Al-Pd-Mn samples with composition Al-72.6 at. %, Pd-22.9 at. %, Mn-4.5 at. % is reported. In the phase diagram of the Al-Pd-Mn ternary alloy, this composition corresponds to the so-called ξ' phase which was described as an icosahedral quasicrystalline approximant. By re-examining the Fourier space by means of X-ray diffraction (powder patterns and single crystal precession patterns), complex structures in close relation with the ξ'-phase have been observed. These long-range order complex structures are described as resulting from a periodic perturbation of the ξ' structure along the c direction. Two states with periodicities c (3 + τ) and c (5 + τ) have been observed in this study (τ: golden mean). Structural models based on periodic arrangements of “defects” layers separating layers of phase are proposed. These two states are certainly intermediate states between the phase and the metastable decagonal quasicrystalline phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e2002-00261-3
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Micro-transitions or breathers in L-alanine? (2003)
    Springer
    The European physical journal 37 (2003), S. 375-382 
    Details
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The lattice dynamics of crystalline L-alanine shows unusual features tentatively assigned to a localization of vibrational energy. However, other properties alternatively suggest the existence of a second order phase transition undetected in previous crystallographic work. In this paper, we present the results of a high resolution X-ray diffraction study down to 10 K, together with new structure determinations at intermediate temperatures. The data rule out the hypothesis of a conventional structural phase transition. No change in the space group symmetry is observed and an anomalous decrease of the lattice parameter c in discrete steps is discovered when heating the crystal from 10 K to room temperature. It could be ascribed to a progressive conformational change of the NH3 + group of the zwitterionic molecule. An analysis of the physical properties of crystalline L-alanine suggests the existence of a strong dynamic Jahn-Teller-like effect owing to the NH3 + charge-lattice coupling. This would explain both the splitting of some vibrational states and properties related to a microscopic lattice instability like the onset of depolarization in the transmitted light below ~250 K.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e2004-00069-1
    Library Location Call Number Volume/Issue/Year 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...