Inelastic x-ray scattering measurements to study lattice dynamics of negative thermal expansion material ScF$_{3}$

POSTER

Abstract

Thermal expansion is one of the best-known material properties. Although the positive thermal expansion (PTE), a tendency for a solid material to grow when heated, is the most common type, there are some materials which show negative thermal expansion (NTE). NTE is one of the new and exciting fields of materials physics. Strong, thermally persistent, isotropic NTE is unusual and has been observed in only a handful of materials. Here we present inelastic x-ray scattering (IXS) measurement results of single crystal ScF$_{3}$ which has strong, persistent NTE down to very low temperature. We observe softening of the phonons responsible for NTE as the temperature is lowered. The low temperature results data also show the appearance of an elastic peak which is especially strong at M and R points of reciprocal space. The results of the experiment may explain an unusual mechanical behavior of the material.

Authors

  • Sahan Handunkanda

    University of Connecticut

  • Jason Hancock

    University of Connecticut

  • Ayman Said

    Advanced Photon Source, Argonne National Laboratory

  • Andrew Duffy

    Massachusetts Institute of Technology, Columbia University, Central Connecticut State University, Boston College, Chestnut Hill, MA 02467, Wheaton College, Harvard University, Physics Department, Boston University, Mechanical Engineering, Boston University, Boston University, Physics Department, Boston University, Electrical Engineering Department, Boston University, Biomedical Engineering Department, Boston University, Mechanical Engineering Department, Kirensky Institute of Physics, Krasnoyarsk, Siberia, Northeastern University, Rochester University, Boston University, Bridgewater State University