Terahertz spectroscopy of central and soft phonon modes in LuFe2O4

• Published in: Applied physics. A, Materials science & processing Materials science & processing, 2009-09, Vol.96 (4), p.893-898
• Main Authors: Li, S. Z., Luo, S. J., Fu, R., Jin, B. B., Wang, K. F., Liu, J.-M., Ding, J. F., Li, X. G.
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Charge; Condensed Matter Physics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Correlation; Dielectric properties of solids and liquids; Dielectrics; Dielectrics, piezoelectrics, and ferroelectrics and their properties; Displacement; Exact sciences and technology; Ferroelectricity; Ferroelectricity and antiferroelectricity; Fluctuation; Machines; Magnetic properties; Magnetic properties and materials; Magnetomechanical and magnetoelectric effects, magnetostriction; Manufacturing; Nanotechnology; Optical and Electronic Materials; Permittivity (dielectric function); Physics; Physics and Astronomy; Processes; Spectroscopy; Surfaces and Interfaces; Thin Films
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-009-5315-y

The terahertz dielectric response of LuFe 2 O 4 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 TO 1 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 TO 1 mode and the spin/charge fluctuations revealed recently. Finally, the magnetic property at below ∼240 K is discussed.