Relaxor properties of Ba-based layered perovskites

Dielectric Relaxation Phenomenon in Ferroelectric Perovskite-related Structures

“…However, the substitution of Ca 2+ for Bi 3+ in the bismuth layers increases the electrical conductivity. The Aurivillius family exhibit a dielectric behavior characteristic for ferroelectric relaxors (Miranda et al, 2001;Kholkin et al, 2001), e.g. i) marked frequency dispersion in the vicinity of temperature (T m ) where the real part of the dielectric permittivity (ε') shows its maximum value, ii) the temperature of the corresponding maximum for ε' and the imaginary part of the dielectric permittivity (ε'') appears at different values, showing a frequency dependent behavior, iii-the Curie-Weiss law is not fulfilled for temperatures around T m .…”

“…i) marked frequency dispersion in the vicinity of temperature (T m ) where the real part of the dielectric permittivity (ε') shows its maximum value, ii) the temperature of the corresponding maximum for ε' and the imaginary part of the dielectric permittivity (ε'') appears at different values, showing a frequency dependent behavior, iii-the Curie-Weiss law is not fulfilled for temperatures around T m . The materials have attracted considerable attention due to their large remanent polarization, lead-free nature, relatively low processing temperatures and other characteristics (Miranda et al, 2001;Kholkin et al, 2001;Lee et al, 2002;Nelis et al, 2005;Huang et al, 2006;Watanabe et al, 2006). The origin of the relaxor behavior for these materials has been associated to a positional disorder of cations on A or B sites of the perovskite blocks that delay the evolution of long-rage polar ordering (Miranda et al, 2001).…”

“…The materials have attracted considerable attention due to their large remanent polarization, lead-free nature, relatively low processing temperatures and other characteristics (Miranda et al, 2001;Kholkin et al, 2001;Lee et al, 2002;Nelis et al, 2005;Huang et al, 2006;Watanabe et al, 2006). The origin of the relaxor behavior for these materials has been associated to a positional disorder of cations on A or B sites of the perovskite blocks that delay the evolution of long-rage polar ordering (Miranda et al, 2001). For BaBi 2 Nb 2 O 9 ceramics , it has been studied the frequency relaxation of the complex dielectric permittivity in wide temperature and frequency ranges.…”

Dielectric relaxation and relaxor behavior in bilayered perovskites

“…The value of T m is ϳ466 and ϳ529 K at 100 Hz and 1 MHz, respectively, showing a shift of temperature of approximately 63 K, which is in good agreement with previous reports, 3 but lower than that of other relaxor ceramics. 8 the ferroelectric-paraelectric transition. At the higher temperature zone an abrupt increase of Љ is observed, especially in the low frequency range, which could be associated to the conductivity losses.…”

“…8 It has been reported 8 that the incorporation of barium to the SrBi 2 Nb 2 O 9 system provides a higher frequency dependence of the dielectric parameters, showing a relaxorlike ferroelectric. This behavior could be explained by considering the incorporation of a bigger ion into the A site of the perovskite block.…”