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Title: High-pressure structural study of MnF2

In this study, manganese fluoride (MnF2) with the tetragonal rutile-type structure has been studied using a synchrotron angle-dispersive powder x-ray diffraction and Raman spectroscopy in a diamond anvil cell up to 60 GPa at room temperature combined with first-principles density functional calculations. The experimental data reveal two pressure-induced structural phase transitions with the following sequence: rutile → SrI2 type (3 GPa)→ α–PbCl2 type (13 GPa). Complete structural information, including interatomic distances, has been determined in the case of MnF2 including the exact structure of the debated first high-pressure phase. First-principles density functional calculations confirm this phase transition sequence, and the two calculated transition pressures are in excellent agreement with the experiment. Lattice dynamics calculations also reproduce the experimental Raman spectra measured for the ambient and high-pressure phases. The results are discussed in line with the possible practical use of rutile-type fluorides in general and specifically MnF2 as a model compound to reveal the HP structural behavior of rutile-type SiO2 (Stishovite).
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5]
  1. Carnegie Institute of Washington, Washington, DC (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Univ. of Saskatchewan, Saskatoon, SK (Canada); Canadian Light Sources, Inc., Saskatoon, SK (Canada)
  3. Carnegie Institute of Washington, Washington, DC (United States); Chinese Academy of Sciences (CAS), Hefei (China)
  4. Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
  5. National Technical Univ. of Athens, Athens (Greece)
Publication Date:
OSTI Identifier:
1248280
Report Number(s):
LLNL-JRNL--678301
Journal ID: ISSN 2469-9950; PRBMDO
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 93; Journal Issue: 5; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Research Org:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 58 GEOSCIENCES; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY