High frequency dielectric spectroscopy of relaxor ferroelectrics and related materials

• Published in: The Fifth International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter, and Submillimeter Waves (IEEE Cat. No.04EX828) Vol. 2; pp. 757 - 759 Vol.2
• Main Authors: Bovtun, V., Petzelt, J., Kamba, S., Porokhonskyy, K., Pashkin, A., Veljko, S., Samoukhina, P., Yakimenko, Y.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 2004
• Subjects: Crystalline materials; Dielectric materials; Electrochemical impedance spectroscopy; Ferroelectric materials; Frequency; Infrared spectra; Lattices; Microwave theory and techniques; Relaxor ferroelectrics; Solids
• ISBN: 0780384113; 9780780384118
• DOI: 10.1109/MSMW.2004.1346133

Relaxor and doped incipient ferroelectrics represent the partially disordered solids, where the main lattice periodicity is preserved and only some of the sublattices exhibit disorder. Dielectric response of these polar materials is defined by both crystal lattice dynamics and relaxational processes in a wide frequency range below the phonon frequencies. High frequency part of the response is very important for studying the nature of disorder and the relation between the relaxation processes and the crystal lattice dynamics. Here we analyze the high frequency dielectric response (1 MHz - 100 THz) of model lead-containing perovskite relaxor ferroelectrics (PMN, PLZT), moderately doped incipient ferroelectrics (Sr/sub 1-1.5x/Bi/sub x/TiO/sub 3/ and K/sub 1-x/Li/sub x/TaO/sub 3/) and pyrochlore high-/spl epsiv/ microwave ceramics ((Bi,Zn)/sub 2/(Zn,Nb)/sub 2/O/sub 7/), studied by the coaxial and waveguide microwave methods, time domain THz spectroscopy and infrared reflectivity.