Low frequency elastic and anelastic properties of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mbox{\sffamily\bfseries Pb(Fe}_{\hbox{\sffamily\bfseries\fontsize{12}{12}\selectfont 0.5}} \mbox{\sffamily\bfseries Nb}_{\hbox{\sffamily\bfseries\fontsize{12}{12}\selectfont 0.5}} \mbox{\sffamily\bfseries )O}_{\hbox{\sffamily\bfseries\fontsize{12}{12}\selectfont 3}}$\end{document} ferroelectric ceramics

Pb(Fe0.5Nb0.5)O3 is one of the well studied ferroelectric compound. However, different physical properties of this ceramics were investigated in details, mainly at temperatures in the vicinity of the Curie point, whereas many questions remain about the behavior of physical properties in a wide temperature range, the presence of other phase transitions, types of lattice defects and their effect on macroscopic characteristics, etc. The papers devoted to low frequency elastic and anelastic properties of Pb(Fe0.5Nb0.5)O3 are practically non-existant. Nevertheless, the study of internal friction could give valuable information about different kinds (point, linear and plane) of lattice defects and the changes in the properties of the different phases of investigating ceramics which are related with the several mechanisms measured by the mechanical resonance spectrometer [3]. It is difficult to obtain such results by any other method; moreover sometimes it is impossible at all. In the work, we present results of the measurements of low frequency internal friction Q-1, Young's modulus E, electric permittivity ε and dielectric loss of angle tgδ in the polycrystalline Pb(Fe0.5Nb0.5)O3 ceramic samples in order to understand a nature of lattice defect interactions and mechanism Q-1 at the phase transition in the Curie and Neel points.