TY - JOUR
T1 - Lattice dynamics and thermal transport in multiferroic CuCrO2
AU - Bansal, Dipanshu
AU - Niedziela, Jennifer L.
AU - May, Andrew F.
AU - Said, Ayman
AU - Ehlers, Georg
AU - Abernathy, Douglas L.
AU - Huq, Ashfia
AU - Kirkham, Melanie
AU - Zhou, Haidong
AU - Delaire, Olivier
N1 - Publisher Copyright:
© 2017 American Physical Society.
PY - 2017/2/9
Y1 - 2017/2/9
N2 - Inelastic neutron and x-ray scattering measurements of phonons and spin waves were performed in the delafossite compound CuCrO2 over a wide range of temperature, and complemented with first-principles lattice dynamics simulations. The phonon dispersions and density of states are well reproduced by our density functional calculations, and reveal a strong anisotropy of Cu vibrations, which exhibit low-frequency modes of large amplitude parallel to the basal plane of the layered delafossite structure. The low frequency in-plane modes also show a systematic temperature dependence of neutron and x-ray scattering intensities. In addition, we find that spin fluctuations persist above 300 K, far above the Néel temperature for long-range antiferromagnetic order, TN≃24K. Our modeling of the thermal conductivity, based on our phonon measurements and simulations, reveals a significant anisotropy and indicates that spin fluctuations above TN constitute an important source of phonon scattering, considerably suppressing the thermal conductivity compared to that of the isostructural but nonmagnetic compound CuAlO2.
AB - Inelastic neutron and x-ray scattering measurements of phonons and spin waves were performed in the delafossite compound CuCrO2 over a wide range of temperature, and complemented with first-principles lattice dynamics simulations. The phonon dispersions and density of states are well reproduced by our density functional calculations, and reveal a strong anisotropy of Cu vibrations, which exhibit low-frequency modes of large amplitude parallel to the basal plane of the layered delafossite structure. The low frequency in-plane modes also show a systematic temperature dependence of neutron and x-ray scattering intensities. In addition, we find that spin fluctuations persist above 300 K, far above the Néel temperature for long-range antiferromagnetic order, TN≃24K. Our modeling of the thermal conductivity, based on our phonon measurements and simulations, reveals a significant anisotropy and indicates that spin fluctuations above TN constitute an important source of phonon scattering, considerably suppressing the thermal conductivity compared to that of the isostructural but nonmagnetic compound CuAlO2.
UR - http://www.scopus.com/inward/record.url?scp=85013055723&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.95.054306
DO - 10.1103/PhysRevB.95.054306
M3 - Article
AN - SCOPUS:85013055723
SN - 2469-9950
VL - 95
JO - Physical Review B
JF - Physical Review B
IS - 5
M1 - 054306
ER -