Local and average crystal structure and displacements of La{sup 11}B{sub 6} and EuB{sub 6} as a function of temperature Metadata

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Title

  • Main Title Local and average crystal structure and displacements of La{sup 11}B{sub 6} and EuB{sub 6} as a function of temperature

Creator

  • Author: Booth, C.H.
    Creator Type: Personal
  • Author: Sarrao, J.L.
    Creator Type: Personal
  • Author: Hundley, M.F.
    Creator Type: Personal
  • Author: Cornelius, A.L.
    Creator Type: Personal
  • Author: Kwei, G.H.
    Creator Type: Personal
  • Author: Bianchi, A.
    Creator Type: Personal
  • Author: Fisk, Z.
    Creator Type: Personal
  • Author: Lawrence, J.M.
    Creator Type: Personal

Contributor

  • Sponsor: USDOE Director, Office of Science. Office of Basic Energy Studies. Division of Chemical Sciences (United States)
    Contributor Type: Organization

Publisher

  • Name: Lawrence Berkeley National Laboratory
    Place of Publication: California
    Additional Info: Lawrence Berkeley National Lab., CA (United States)

Date

  • Creation: 2001-01-30

Language

  • English

Description

  • Content Description: Measurements of both the average crystal structure from Rietveld refinement of neutron powder diffraction (NPD) data and the local structure from La L{sub III}-edge x-ray-absorption fine-structure (XAFS) are presented for a La{sup 11}B{sub 6} sample as a function of temperature ({approx}10-320 K). These data are compared to XAFS results on a EuB{sub 6} sample. The single-site La and B positional distribution widths and the La-B and La-La bond length distribution widths and their temperature dependence are compared. This comparison allows an estimate of the La and B site displacements, and we find that these sublattices are only slightly correlated with each other. Moreover, while the temperature dependence of the displacement parameters of the average sites from diffraction fit an Einstein model well, the temperature dependence of the La-B bond length distribution width requires at least two vibrational frequencies, corresponding to the La and B frequencies of the individual sites. XAFS data on EuB{sub 6} indicate that the situation is the same in the Eu compound. In addition, comparisons between data taken below and above the ferromagnetic transition temperature for EuB{sub 6} place stringent limits on the lattice involvement in the associated metal-insulator transition and the ensuing large magnetoresistance effect. This lack of lattice involvement in the magnetoresistance transition is in sharp contrast to the strong lattice involvement observed in the colossal magnetoresistance lanthanum manganese perovskites.
  • Physical Description: vp.

Subject

  • Keyword: Fine Structure
  • Keyword: Magnetoresistance
  • Keyword: Perovskites
  • Keyword: Diffraction
  • Keyword: Lanthanum
  • Keyword: Bond Lengths
  • Keyword: Crystal Structure
  • STI Subject Categories: 36 Materials Science
  • Keyword: Manganese
  • Keyword: Neutrons
  • Keyword: Temperature Dependence
  • Keyword: Distribution
  • Keyword: Transition Temperature Hexaborides Colossal Magnetoresistance Xafs
  • Keyword: Hexaborides Colossal Magnetoresistance Xafs

Source

  • Journal Name: Physical Review B; Journal Volume: 63; Journal Issue: 22; Other Information: Journal Publication Date: June 1, 2001

Collection

  • Name: Office of Scientific & Technical Information Technical Reports
    Code: OSTI

Institution

  • Name: UNT Libraries Government Documents Department
    Code: UNTGD

Resource Type

  • Article

Format

  • Text

Identifier

  • Report No.: LBNL--47280
  • Grant Number: AC03-76SF00098
  • DOI: 10.1103/PhysRevB.63.224302
  • Office of Scientific & Technical Information Report Number: 785262
  • Archival Resource Key: ark:/67531/metadc716612