Synchrotron x-ray study of lattice vibrations in CdCr2O4

TL;DR

This study uses inelastic x-ray scattering to examine lattice vibrations in CdCr2O4, revealing phonon energy shifts associated with a spin-Peierls transition and symmetry lowering.

Contribution

It provides detailed insights into phonon behavior across a spin-Peierls transition in a geometrically frustrated magnet using synchrotron x-ray techniques.

Findings

Phonon energies shift at zone boundaries during the transition.

The shifts are explained by symmetry lowering effects.

Lattice vibrations are sensitive to magnetic phase changes.

Abstract

Using inelastic x-ray scattering we have investigated lattice vibrations in a geometric frustrated system CdCr2O4 that upon cooling undergoes a spin-Peierls phase transition at TN = 7.8 K from a cubic and paramagnetic to a tetragonal and Neel state. Phonon modes measured around Brillouin zone boundaries show energy shifts when the transition occurs. Our analysis shows that the shifting can be understood as the ordinary effects of the lowering of the crystal symmetry.