0000000000880707
AUTHOR
I. E. Tumanov
Dielectric Properties of PMN-PNN+2%Li2O Ferroelectric Ceramics at Low and Infra-Low Frequencies
AbstractA study of dielectric response to weak and strong measuring fields at temperatures of the diffuse phase transition in lead-magnesium niobate—lead-nickel niobate (PMN-PNN) containing an admixture of lithium is reported. A relaxor behaviour of the ceramic compound manifesting itself by a substantial shift of the temperature of dielectric permittivity maximum with field intensity and frequency is detected. Specific features of the dielectric nonlinearity observed at temperatures considerably higher than the temperature of the low-frequency dielectric permittivity maximum are related to extension of the range of phase transition to higher temperatures. This extension is related to forma…
Dielectric properties of PMN+2%Li 2 O at low frequencies
The reported study is focused on effects of the admixture of lithium (2% Li2O) on the low-frequency dielectric response in lead magnesium niobate ceramics over the 100 -300 K range of temperature. The obtained results reveal an essential thermal broadening of the e′(ν) spectra specific to relaxor ferroelectrics. Dispersion Δe′ = e′1Hz-e′1kHz and values of e′′(ν) in lead magnesium niobate ceramics containing Li are well described by the Cole-Cole equation at temperatures below the e′(T) maximum. Based on the analysis of the experimental data admixture of lithium is suggested to promote formation of domains in lead magnesium niobate ceramics (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Relaxation of Polarization at the Broad Phase Transition in Modified PMN Ferroelectric Ceramics
The reported study is focused on effects of relaxation of polarization within the range of the broad phase transition at strong sinusoidal measuring fields in modified lead magnesium niobate ceramics. The obtained results reveal an essential thermal broadening of the ϵ′(E) spectra specific to relaxor ferroelectrics. Temperature dependence of ϵ′ eff (T) at medium fields shows two broad maximums – at Tm and at 40°C. On the basis of analysis of the experimental data, admixture of lithium is suggested to promote formation of domains in lead magnesium niobate ceramics.