Substitution of alkali earth metal ion of Sr2+, in the Pb2+ site of Pb(Mg1/3Nb2/3)O3–PbTiO3 is expected to induce functional modulations in the system. Doping of 4 at.% of Sr2+ in 0.68PMN-0.32PT was carried out to lower the transition temperature, and to investigate the intended ferroelectric and dielectric variations. Excellent relaxor property was observed in the doped sample without appreciable reduction in remnant polarization. Doping with Sr2+ led to a reduction in transition temperature from 165 °C to 117 °C. Doped sample exhibited remnant polarization Pr = 16.2 μC/cm2, Squareness factor (Rsq) = 1.05 and Relaxor exponent (γ) around 2. Modulation in the functional response was exhibited by the doped composition, having low transition temperature, and its prospect in electrocaloric applications was analyzed. © 2019 Elsevier Ltd and Techna Group S.r.l.

Mamidanna Sri Ramachandra Rao

Department Of Physics

Kanikrishnan Sethupathi

Pius Augustine

Shibnath Samanta

Dielectric properties

Ferroelectricity

LEAD TITANATE

Metal ions

Metals

Perovskite

Polarization

Temperature

ALKALI EARTH METAL

ELECTROCALORIC

Ferroelectric property

Functional applications

FUNCTIONAL RESPONSE

LOW-TRANSITION TEMPERATURE

RELAXOR PROPERTIES

Remnant polarizations

Modulation

Fulltext

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Ceramics International

The studies on the effect of simultaneous doping of donor (Nb) and acceptor (Fe) (0–8&nbsp;at.% of each dopant) in PLZT (Pb0.97La0.02Zr0.52Ti0.48O3), on the dielectric response, ac conductivity and ferroelectricity are reported in this article. It is observed that the value of dielectric constant decreases, dielectric loss increases (moderately) and coercive field increases upon doping of Nb and Fe together. These indicate a hardening like effect as a result of the donor–acceptor co-doping. The ferroelectric to paraelectric phase transition occurs at lower temperatures for higher doping concentrations. For undoped PLZT the Curie temperature is around 353&nbsp;°C which shifts to 305&nbsp;°C for 8% Nb–Fe co-doped PLZT. Microstructure studies on the surface, as well as the interior of the samples are carried out which reveal a clear difference. The grain size is observed to decrease with doping concentration. The “true switchable polarization” is deduced by positive up negative down (PUND) tests and found to decrease with doping. Fatigue behavior is found to be positively enhanced upon co-doping of 2% Nb and Fe. Leakage current tests are carried out and it is found that the samples become more ‘leaky’ upon co-doping of Nb and Fe. The energy storage density is also investigated for these Nb–Fe co-doped PLZT ceramics. The highest recoverable energy storage density is observed for 2% Nb–Fe co-doped PLZT sample and it is around 134&nbsp;mJ/cm3 with an efficiency of 0.28. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.

Journal of Materials Science: Materials in Electronics

Effect of Nb and Fe co-doping on microstructure, dielectric response, ferroelectricity and energy storage density of PLZT

Synthesis of single phase (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 ceramics with enhanced electrical response was achieved by excluding excess PbO from the precursor, making them suitable for device applications. This report is an inquiry into the effect of high temperature stabilization used for the realization of single phase PMN-PT ceramics on the electrical properties exhibited by the compositions in the morphotropic phase boundary. Functional response exhibited by the high temperature stabilized ceramics is correlated with the structural fluctuations in the morphotropic phase boundary and the grain pattern observed in the microstructure. Gradual transition from diffuse relaxor ferroelectric system to normal ferroelectric system was also studied. Enhanced ferroelectric response of the composition x=0.35 (Psat=32.03 μC/cm2, Pr=25.11 μC/cm2, EC=6.04 kV/cm, Rsq=1.28, Absolute area=3768, range of electric field=−37 to +37 kV/cm and recoverable energy density= 59.86 mJ/cm3), the improved dielectric behavior of the composition x=0.325 (εr(max)=15,703, Tanδmax=0.02 and γ=1.79 (at 1 kHz)) and the high piezoelectric coefficient d33 (390 pC/N and 365 pC/N for x=0.325 and x=0.35 respectively), obtained in the study have confirmed the device worthiness of the synthesized ceramic compositions. This study was carried out to establish that, modulated high temperature synthesis will not deteriorate the electrical properties of the lead based system like PMN-PT, rather will assist the completion of perovskite phase formation, and thus enhance the functional response of the ceramic. © 2017 Elsevier Ltd and Techna Group S.r.l.

Enhanced functional response of high temperature stabilized (1-x)PMN-xPT ceramics

We report on the synthesis and stabilization of device quality PMN–PT ceramics prepared by columbite route. Synthesis chemistry of columbite precursor, MgNb2O6, is analyzed, and a partial covering method for creating Pb atmosphere during calcination and sintering along with modulated heating have been tried, to realize pyrochlore-free PMN–PT having good ferroelectric properties. X-ray diffraction, Raman and SEM analysis, and hysteresis studies established that pure stoichiometric perovskite phase PMN–PT with excellent ferroelectric properties (Psat ~31.5 µC/cm2, Pr ~24.7 µC/cm2 and Ec ~6.1 kV/cm) could be realized through the novel modulated heating and stabilization procedures. Modulated heating may be applied for the synthesis of other lead based mixed perovskites as well. © 2015 Elsevier Ltd and Techna Group S.r.l.

Realization of device quality PMN–PT ceramics using modulated heating method

High-energy storage performance in lead-free (1-x)BaTiO 3 -xBi(Zn 0.5 Ti 0.5 )O 3 relaxor ceramics for temperature stability applications

Impact of Ni dopant on structure and electrical properties of PMN-0.1PT ceramics

Modulations in relaxor nature due to Sr2+ doping in 0.68PMN-0.32PT ceramic

Journal	Data powered by TypesetCeramics International
Publisher	Data powered by TypesetElsevier Ltd
ISSN	02728842
Open Access	Yes