Distribution of the iron dopant in barium titanate ceramic, determined by the scanning transmission electron microscope

Knauer, U.

doi:10.1002/pssa.2210530122

Cited by 25 publications

(13 citation statements)

References 1 publication

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“…Issa et a/(1984) concluded from their studies that the formation of defective grain boundary layers at the boundary of the grain was responsible for the depression of ema~-These large boundary layers with lattice distortion were assumed to be compositionally different from the interior of the grain. A similar conclusion was arrived at by Knauer (1979) for BaTiO3 doped with Fe203. From the above results, it is reasonable to assume that the decrease in spontaneous polarization values consequent on decrease of permittivity values of the doped samples of NaVO3 and LiVO 3 is due to the formation of defective grain boundary layers.…”

Section: Resultssupporting

confidence: 84%

Effect of Fe2O3 addition on the ferroelectricity of sodium and lithium vanadates

Krishnan

Seshamma

1991

Bull. Mater. Sci.

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Spontaneous polarization and eoereivity of sodium and lithium vanadates were found to be remarkably dependent on the solid solutions formed between the respective vanadates and Fe203. The decreasing trend in Ps and the depression of Tc observed for increasing concentrations of the offvalent impurity were attributable to the formation of defective grain boundary layers of low electric polarization.

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Section: Resultssupporting

confidence: 84%

Effect of Fe2O3 addition on the ferroelectricity of sodium and lithium vanadates

Krishnan

Seshamma

1991

Bull. Mater. Sci.

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“…The assumed migration of ferro and especially ferri ions into the BTO lattice leads to a structural phase transition and displacement of the ions inside the lattice, thereby changing the local dipole structure in the grains. The distribution of iron at grain boundaries affects the electrical properties of the system as well, reducing mobility of the walls between polarization domains [29,30]. This is in agreement with the defective dipole model [31], according to which iron effectively immobilizes dipoles in its surroundings.…”

Section: Resultssupporting

confidence: 78%

Evolution of structural and functional properties of the Fe/BaTiO3 system guided by mechanochemical and thermal treatment

et al. 2020

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Multiferroic systems are attractive to the researches worldwide due to diversity of existing applications, as well as possible novel ones. In order to contribute to understanding of the processes that take place within the structure of such a system, we subjected it to mechanochemical activation and thermal treatment. Powdery mixtures of iron and barium titanate in a mass ratio of 30% Fe and 70% BaTiO3 were activated in a planetary ball mill for time duration of 30 to 300 min and subsequently sintered at 1200?C in the atmosphere of air. During the activation the system undergoes structural phase transitions, whereby the content of iron and its oxides changes. The highest Fe content was observed in the sample activated for 270 min, with local maxima in crystallite size and microstrain values and a minimum in dislocation density. The complex dielectric permittivity changes in the applied radio frequency field, rangingfrom 176.9 pF/m in thesample activated for 90 min to 918.1 pF/m in the sample activated for 180 min. As the frequency of the field increases, an exponential decrease in the magnetic with a simultaneous increase in the electrical energy losses is noticeable. The system exhibits ferromagnetic resonance, whereby longer activation in the mill shifts the resonant frequency to higher values. Negative electrical resistance was observed in all analyzed samples. The activation time changes both the demagnetization temperature and the Curie temperature of the samples undergoing heating and cooling cycles in the external permanent magnetic field. Curie temperature is the highest in the sample activated for 240 min. Thermal treatment increases the initial magnetization of all samples, with the most pronounced increase of ~95% in the sample activated for 300 min. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. OI 172057]

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“…3). A broadening and flattening of the maximum of ε(T) and a shift of the Curie temperature T c have also been observed in Fe-doped BaTiO 3 ceramics [10,11]. Similar effects also exist in the potassium tantalite niobate [12] and in several oxides with perovskite structure: Nb:KTaO 3 , Cu,La:PbTiO 3 [13].…”

Section: Resultsmentioning

confidence: 53%

Ferroelectric Phase Transition in Cu-doped BaTiO3 Crystals

Ouedraogo

Palm²,

Chanussot³

2009

J. Sci. Res.

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The paper examines the ferroelectric-paraelectric phase transition in Cu:BaTiO 3 single crystals. Using thermo-currents and dielectric measurements, we found for pure samples the phase transition temperature to be close to Curie temperature (T c =120°C) with an anisotropy of the dielectric constantε.The lowering of temperature T m , corresponding to the maximum of pyroelectric signal, with the increase of concentration of impurities is confirmed by measurements of ε. Moreover, the ε(T) curves show progressive broadening as well as higher peak with the increase of impurity concentration, and the transition becomes more and more diffuse. The same effect occurs when the samples are subjected to a laser irradiation (λ=5145Ǻ). During annealing, crystals lose copper and T m is thereafter observed to increase again. BaTiO 3 is a displacive ferroelectric (having high permittivity k-values) which undergoes a first order phase transition. Ions substitutions have an effect on the lattice dynamics attributed to charge transfer to Ti and a lowering of elastic forces in BaTiO 3 .

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Distribution of the iron dopant in barium titanate ceramic, determined by the scanning transmission electron microscope

Cited by 25 publications

References 1 publication

Effect of Fe2O3 addition on the ferroelectricity of sodium and lithium vanadates

Effect of Fe2O3 addition on the ferroelectricity of sodium and lithium vanadates

Evolution of structural and functional properties of the Fe/BaTiO3 system guided by mechanochemical and thermal treatment

Ferroelectric Phase Transition in Cu-doped BaTiO3 Crystals

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