Heat-diffusion central peak in the dielectric susceptibility of ferroelectric materials

M. Fally, W. Schranz, D. Havlik
1996 Physical Review B (Condensed Matter)  
Recently, low-frequency measurements ͑0.1-Hz region͒ of the elastic susceptibility in KSCN near the orderdisorder phase transition at T c ϭ410 K revealed a relaxation that could be explained by entropy fluctuations. We present a phenomenological theory describing the heat-diffusion central peak in the macroscopic ͑qϭ0͒ dielectric susceptibility. It results from the Landau free energy and the heat-diffusion equation. The model predicts a relaxation in the ferroelectric phase at low frequencies
more » ... t low frequencies that depends on sample size. It does not follow a simple Debye behavior, but reveals a long high-frequency tail. ͓S0163-1829͑96͒00822-3͔
doi:10.1103/physrevb.53.14769 pmid:9983271 fatcat:z7jlraeii5bpxduxg2lamx3te4