Search results for "Dielectric response"
showing 10 items of 15 documents
The effect of bias field on the dielectric response of Ba0.95Pb0.05TiO3+Со2О3
2021
The nature of the dielectric response in ferroelectric ceramics Ba0.95Pb0.05TiO3+Со2О3 (BPTC) under the influence of a constant bias field EB in the phase transition region is studied. It is found ...
Long-lived dynamic heterogeneity in a relaxor ferroelectric
1998
The polydispersive dielectric response of the relaxor ferroelectric lead magnesium niobate was investigated using nonresonant spectral hole-burning experiments. Using large alternating electric fields, specific parts of the relaxation-time distribution could be addressed selectively. This provides evidence for the dynamic heterogeneity of the dipolar reorientation process. The refilling of single as well as of double holes was much slower than the time scale set by the pump frequencies. Upon refilling, the holes exhibited no signs of spectral broadening. The present findings suggest a speedup of polarization response associated with a domain-wall depinning that is induced by the hole-burnin…
Polarization of SrBi 2 Ta 2 O 9 ceramics at infra‐low frequencies
2009
Dielectric response in the SrBi2Ta2O9 ceramics is studied over a wide range of temperatures at fields up to Emax ≈ 18 kV/cm. Dependence of dielectric permittivity on field intensity is analyzed at different temperatures. A series of polarization loops are obtained at frequencies 0.1 Hz, 1 Hz, and 10 Hz. The hysteresis at switching polarization is displayed by the shape of polarization loops changing with the field amplitude from bi-angles to quasi-saturated loop patterns of a high degree of rectangularity. The ratio of remnant polarization to maximum polarization as function of field amplitude is presented. Thermal behaviour of the coercive field and the half-width of polarization loops is …
Dielectric properties of PMN+2%Li 2 O at low frequencies
2012
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)
Dielectric and acoustic properties of modified barium titanate ceramics
2019
This work was supported in part by the Ministry of Education and Science of the Russian Federation.
Dielectric study of supercooled triphenylphosphite and butyronitrile: Comparison with a mesoscopic model
1996
Abstract Dielectric relaxation has been studied in the supercooled liquids triphenylphosphite (TPP) and butyrontrile (BN). BN is relatively strong according to Angell's classification and can be characterized by a fragility index m = 47. TPP, on the other hand, appears to be the most fragile non-polymeric liquid studied so far (m = 160). The dielectric response of the two glass-formers exhibits different degrees of non-exponentiality which is analyzed in terms of a mesoscopic model of dynamically correlated domains. The relation of this model to the strong versus fragile liquid classification scheme is discussed.
The Effect of Bias Field on Dielectric Response in Lead Ferrotantalate Ceramics
2011
Studies of dielectric properties of PbFe1/2Ta1/2O3 ceramics at low- and infra-low-frequencies under bias field over a wide range of temperatures are reported. Applied bias field is found to broaden the ϵ′(Т) maxima shifting positions Тm of the maximums to higher temperatures. Additional anomalies in the dielectric response are revealed at T<Тm. The anomalies in the vicinity of Тm are related to structural change at phase transition, while those observed at TТm – to magneto-electric interactions in PbFe1/2Ta1/2O3.
Dielectric properties of Pb(Fe1/2Ta1/2)O3ceramics over 70–300 K temperature range
2011
The studies of dielectric response in ferromagnetic lead ferrotantalate Pb(Fe1/2Ta1/2)O3 are reported over a wide range of temperature under the applied bias field. The features of dielectric nonlinearity deduced from behaviour of reverse e'(E=) curves at different temperatures, including regions of ferroelectric phase transition and vicinity of the Neel point, are examined. Obtained results indicate a substantial broadening of the ferroelectric phase transition. The results are discussed with respect to effects of ferroelectric ordering in relaxor materials of such kind.
Reversive Dielectric Response in xPZN-(1 − x) PSN Ceramics
2006
The effects of bias fields E= on dielectric response of xPbZn1/3Nb2/3O3-(1 − x)PbSc1/2 Nb1/2O3 ferroelectric solid solutions of x = 0, 0.05, 0.2, and 0.5 studied at temperatures of diffused phase transitions are reported. The thermal interval of the existence of a relaxor phase in the system is found to shrink with the concentration of PbZn1/3Nb2/3O3. The change of the ratio of zinc-lead and scandium-lead niobate components is deduced to change the features of the transition to polarised state from first-order to second-order transition.
Specifics of polarisation switching in PbNi1/3Nb2/3O3–PbTiO3–PbZrO3 ferroelectric ceramics
2004
Abstract The growing interest in disordered relaxor ferroelectrics is due to unusual properties mainly related to the existence of broad phase transitions characteristic to the systems. The effects of bias field on the dielectric response and polarisation switching are studied in the 0.5 PbNi 1/3 Nb 2/3 O 3 – x PbTiO 3 –(0.5− x ) PbZrO 3 system at different PbTiO 3 :PbZrO 3 ratio. Thermal behaviour of normalised remnant polarisation P r / P max of compositions with content of lead titanate x =0.33 and x =0.35 at frequency 0.1 Hz and different values of field E o are measured. Results of measured polarisation and depolarisation currents are compared with characteristics of polarisation switc…