thermal transport ; lattice specif heat ; phonons ; ab initio ; Debye model
Vědní obor RIV
BM - Fyzika pevných látek a magnetismus
Institucionální podpora
UFM-A - RVO:68081723
UT WOS
000304789500033
Anotace
The heat transport in a single-crystal of CsNiF3 has been performed in the temperature range from 2 K to 7 K in a zero magnetic field, B = 0, as well as in sufficiently large magnetic fields, B = 6 T and 9 T, inducing the ferromagnetic ground state along the hard c-axis. CsNiF3 represents an S = 1 quasi-one-dimensional XY ferromagnet with the intra-chain exchange coupling J/k(B) approximate to 24 K, single-ion anisotropy D/k(B) approximate to 8 K, and ordering temperature T-N = 2.7 K. Comparison of the phonon and magnon velocities suggests that phonons are the main heat carriers in this magnetic insulator. The thermal conductivity in B = 0 was analysed in the frame of a standard Debye model. The temperature dependence of the effective phonon mean free path was calculated from the experimental data, and the enhancement of the phonon mean free path in B not equal 0 was obtained, indicating that magnons act as scattering centers for phonons.
