Dielectric spectroscopy of Ba(B1/2′B1/2″)O3 complex perovskite ceramics: Correlations between ionic parameters and microwave dielectric properties. I. Infrared reflectivity study (1012–1014 Hz)

Publisher Website
Google Scholar
Abstract
An attempt has been undertaken to find a correlation between ionic parameters of ceramic materials and their complex permittivity at microwave frequencies. Ten Ba(B1/2’B1/2‘)O3 complex perovskite compounds (B’=Y3+, In3+, Nd3+, Gd3+; B‘=Nb5+, Ta5+ and B’=Mg2+, Cd2+, B‘=W6+) are compared in order to study the effect of ionic radii, mass, and valence state on dielectric properties. Fourier transform infrared reflectivity spectra in the 30–4000 cm−1 range were measured and evaluated by means of Kramers–Kronig analysis and classical oscillator fit. The data were extrapolated below the measured frequency range to estimate the intrinsic microwave losses. The correlations between loss, permittivity, ionic size, mass, and effective charge and polar‐phonon mode parameters were investigated. Ionic size was revealed to be the most important parameter, determining the tolerance factor of the structure packing and through this controlling the phonon frequencies and dampings as well as the extrapolated low‐frequency intrinsic permittivity and loss. Nb5+ ions showed systematically higher dampings and greater tendencies towards disorder in comparison with Ta5+ compounds with the same tolerance factor. A steep increase in extrapolated loss with increasing permittivity was observed.

This publication has 26 references indexed in Scilit: