ISSN 1063-7834, Physics of the Solid State, 2014, Vol. 56, No. 11, pp. 2206–2212. © Pleiades Publishing, Ltd., 2014. Original Russian Text © G.A. Komandin, O.E. Porodinkov, L.D. Iskhakova, I.E. Spektor, A.A. Volkov, K.A. Vorotilov, D.S. Seregin, A.S. Sigov, 2014, published in Fizika Tverdogo Tela, 2014, Vol. 56, No. 11, pp. 2135–2141. 2206 1. INTRODUCTION Solid solutions of lead zirconate titanate (PZT) belong to a class of oxygen-octahedral ferroelectric materials, which found a wide practical application due to their pyroelectric, piezoelectric, and nonlinear- optical properties. These materials can be synthesized in a broad range of Zr–Ti concentrations in the form of single crystals, ceramics, and thin films [1]. Ferroelectric lead titanate (PT) has tetragonal symmetry, which is also conserved in the Pb(Zr 1– x Te x )O 3 solid solutions upon doping to x ~ 0.48. The rhombohedral phase prevails in solid solutions at high Zr concentrations (up to 90%) [2]. The orthorhombic phase of the antiferroelectric PbZrO 3 affects the struc- ture of solid solutions at Zr concentrations higher than 90% [3]. Vibrational spectra of the system of bulk sam- ples of the PT and PZT solid solutions are investigated using Raman scattering [4–6] and infrared spectros- copy [7]. The authors of [8, 9] measured the transmis- sion spectra of thin-film PT and PZT samples in the far-infrared range and investigated the temperature evolution of the soft mode parameters. Multilayer heterostructures with thin ferroelectric PZT films are of greatest interest for electronics. The possibility to control the polarization of these films has determined, in particular, their application in capaci- tor cells of nonvolatile ferroelectric random access memories (FRAM) [10–12]. The Pb(Zr, Ti)O 3 thin ferroelectric films are prepared using different tech- niques: vacuum sputtering, chemical vapor deposi- tion, chemical deposition from aerosol sources, etc. [13]. A convenient method for preparing planar PZT films is the chemical deposition from solutions (the sol–gel method) with their characteristic formation temperatures of 400–650°C, which correspond to temperatures of “conventional” production cycles of silicon electronics [14, 15]. An important electrodynamic parameter of these films is permittivity ε'. To determine it in the kilohertz and megahertz ranges, bridge impedance meters are usually used, which, in turn, requires using the metal electrodes. The influence of electrodes on the film struc- ture leads to additional errors in determining ε' [16]. The goal of this study is the contactless determina- tion of electrodynamic parameters of amorphous and polycrystalline PZT films in the terahertz (THz)–infra- red (IR) range, in which the dynamic processes in the crystal lattice form the static permittivity of the film. The studied solid solution of the PbZr 0.52 Ti 0.48 O 3 composition lies in the phase diagram in the region of the morphotropic boundary [17–21], which separates two phases with ferroelectric properties, namely, the rhombohedral one with an increased zirconium con- tent and the tetragonal one with an increased titanium content. This solution has the maximal permittivity in the Pb(Zr 1– x Ti x )O 3 family [22]. 2. PREPARATION OF THE FILMS Three samples of bilayer structures were fabricated for spectral measurements in the THz–IR range. The FERROELECTRICITY Electrodynamic Properties of Lead Zirconate–Titanate Thin Films in the Terahertz Frequency Range G. A. Komandin a , O. E. Porodinkov a, *, L. D. Iskhakova b , I. E. Spektor a , A. A. Volkov a , K. A. Vorotilov c , D. S. Seregin c , and A. S. Sigov c a Prokhorov General Physics Institute, Russian Academy of Sciences, ul. Vavilova 38, Moscow, 119991 Russia * e-mail: oporodinkov@ran.gpi.ru b Fiber Optics Research Center, Russian Academy of Sciences, ul. Vavilova 38, Moscow, 119333 Russia c Moscow State Technical University of Radio Engineering, Electronics and Automation, pr. Vernadskogo 78, Moscow, 117454 Russia Received May 14, 2014 Abstract—The transmission/reflection spectra of bilayer structures consisting of thin amorphous and poly- crystalline Pb(Zr 0.52 Ti 0.48 )O 3 ferroelectric films deposited on dielectric substrates of magnesium oxide MgO and sapphire α-Al 2 O 3 were measured in the frequency range of 5–4000 cm –1 . Based on these spectra and using the dispersion analysis method, the spectra of complex dielectric permittivity ε*(ν) and dynamic con- ductivity σ'(ν) of the films were simulated, the electrodynamic parameters of the films were determined, and the dielectric dispersion responsible for the formation of static permittivity was found. DOI: 10.1134/S106378341411016X