Terahertz spectroscopy of central and soft phonon modes in LuFe2O4.

Authors :: Li, S. Z.
Luo, S. J.
Fu, R.
Jin, B. B.
Wang, K. F.
Liu, J.-M.
Ding, J. F.
Li, X. G.
Source :: Applied Physics A: Materials Science & Processing. Sep2009, Vol. 96 Issue 4, p893-898. 6p. 1 Diagram, 4 Graphs.
Publication Year :: 2009
Abstract: The terahertz dielectric response of LuFe2O4 is investigated by terahertz time-domain spectroscopy over a temperature range of 6–290 K. It is revealed that besides the central mode associated with the charge-ordered state, a soft TO1 mode at below ∼240 K is identified indicating the existence of displacing ferroelectricity, in addition to the charge-ordering-induced ferroelectricity at below 320 K. The anomaly of the soft mode at ∼180 K reflects the magnetoelectric correlation between the soft TO1 mode and the spin/charge fluctuations revealed recently. Finally, the magnetic property at below ∼240 K is discussed. [ABSTRACT FROM AUTHOR]