Anomalous dielectric behavior of poled K0.5Bi0.5TiO3 ceramics

Badole, Manish; Dwivedi, Sushmita; Kumar, Sunil

doi:10.1016/j.ceramint.2021.12.336

Cited by 9 publications

(5 citation statements)

References 33 publications

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“…The poled K5BA-T sample showed an additional dielectric anomaly, which suggests an electric field-induced phase transition in the K5BA-T sample. Similar behavior was observed in previous studies on KBT-based piezoceramics. , A small hump in the dielectric graph for the depoled sample ( d 33 = 0) could be due to the residual phase that had evolved during poling (Figure d).…”

Section: Resultssupporting

confidence: 87%

“…These results indicate that the reaction temperatures affect the structural behavior of the target material. The effects of sintering parameters on dielectric and piezoelectric properties were reported in our previous study …”

Section: Experimental Sectionmentioning

confidence: 99%

“…Another study by Kim et al observed a phenomenal improvement in the piezoelectric performance in the [001]-textured KNN-based solid solution . Potassium bismuth titanate (K 0.5 Bi 0.5 TiO 3 , (KBT)) is another important lead-free alternative that shows relaxor ferroelectric behavior with high tetragonal symmetry ( c / a ratio ∼ 1.02) at room temperature. , KBT exhibits diffuse phase transition ( T m ∼ 380 °C), and high depolarization temperature ( T d ∼ 320 °C) compared to BT- and NBT-based piezoceramics . However, the inferior piezoelectric performance of KBT-based ceramics restricts their use in commercial applications.…”

Section: Introductionmentioning

confidence: 99%

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High-Performance [00l]-Textured BiAlO₃-Doped K_0.5Bi_0.5TiO₃ Ceramics

Badole,

Vasavan,

Saxena

et al. 2023

ACS Appl. Electron. Mater.

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grain-oriented 0.95K 0.5 Bi 0.5 TiO 3 −0.05BiAlO 3 (named K5BA-T) ceramics were prepared via the reactive template grain growth (RTGG) and tape casting technique. High-aspect-ratio K5BA powder was prepared using a plate-shape 4layer aurivillius oxide (K 0.5 Bi 4.5 Ti 4 O 15 ) powder as the template. The effects of grain morphology modification and texturing on the structural, dielectric, and piezoelectric properties of K5BA-T were systematically investigated. The average plate size of ∼6.5 μm with a thickness of ∼400 nm was observed in the K5BA sample. X-ray diffraction (XRD) and bulk texture measurements confirmed the texturing of K5BA-T in the [00l] crystallographic direction with a calculated Lotgering factor of ∼80%. Two anomalies in the temperature-dependent dielectric plot of the poled K5BA-T sample signified additional poling-induced phase transition. A lower value of room-temperature (RT) dielectric constant (ε r ) of ∼ 200 (at 1 MHz) and a higher piezoelectric charge coefficient (d 33 ) of ∼145 pCN −1 were obtained in the poled K5BA-T ceramic compared to that of the 0.95K 0.5 Bi 0.5 TiO 3 −0.05BiAlO 3 ceramic with randomly oriented grains (named K5BA-R). Consequently, the piezoelectric voltage coefficient (g 33 ) estimated for the textured ceramic showed a 650% increment (g 33 ∼ 80 × 10 −3 V mN −1 ) over the K5BA-R sample (g 33 ∼ 12.5 × 10 −3 V mN −1 ). The transduction coefficient (d 33 •g 33 ) of K5BA-T ceramic was calculated to be ∼11 600 × 10 −15 m 2 N −1 , which is nearly 9 times higher compared to its random counterpart. Further, a piezodevice fabricated using poled ceramic for energy harvesting showed an output voltage of ∼7 V with a current response of ∼2 μA under normal finger-tapping motion.

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Section: Resultssupporting

confidence: 87%

Section: Experimental Sectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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High-Performance [00l]-Textured BiAlO₃-Doped K_0.5Bi_0.5TiO₃ Ceramics

Badole,

Vasavan,

Saxena

et al. 2023

ACS Appl. Electron. Mater.

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“…All samples show diffuse phase transitions with frequency dispersion, signifying the relaxor–ferroelectric‐type behavior. In K 0.5 Bi 0.5 TiO 3 piezoceramics, the heterogeneous distribution of A‐site cations (K + and Bi 3+ ) in the ABO 3 structure disrupts the long‐range ordering, which leads to the creation of polar nano‐regions 30 . No significant variation was noticed in the temperature of dielectric maximum ( T m ) value with grain morphology change.…”

Section: Resultsmentioning

confidence: 99%

“…29 Potassium bismuth titanate (K 0.5 Bi 0.5 TiO 3 ) is another promising member of the lead-free piezoelectric family, which shows high tetragonal symmetry (c/a ∼ 1.02) along with a high temperature of dielectric maxima (T m ∼ 380 • C) and high depolarization temperature (T d ∼ 320 • C) in comparison with other counterparts. 30,31 However, no systematic study on the effects of grain morphology on the dielectric and piezoelectric properties of K 0.5 Bi 0.5 TiO 3 (KBT) ceramics has been reported to the best of our knowledge. Herein, we report the fabrication and performance of KBT piezoceramics with cuboid (KBT-C), rod (KBT-R), and plate (KBT-P)-shaped microstructures.…”

Section: Introductionmentioning

confidence: 99%

Grain morphology‐dependent dielectric and piezoelectric properties of lead‐free KBT ceramics

Badole,

Vasavan,

Saxena

et al. 2023

J Am Ceram Soc.

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K0.5Bi0.5TiO3 ceramics with cuboid (KBT‐C), rod (KBT‐R), and plate (KBT‐P)‐shaped grains were fabricated via solid‐state reaction and reactive template grain growth (using K2Ti6O13 and K0.5Bi4.5Ti4O15) methods, and the strong dependence of electrical properties on the grain morphology was demonstrated. The average grain sizes of KBT‐R, KBT‐P, and KBT‐C were ∼30 ± 10 μm, 7 ± 1 μm, and 350 ± 50 nm, respectively. While the room temperature dielectric constant decreased for KBT‐R (∼240) and KBT‐P (∼230) from ∼500 for KBT‐C, a significant enhancement in the piezoelectric charge coefficient (d33) was noticed for KBT‐R (∼95 pC/N) and KBT‐P (∼105 pC/N) samples compared to that of KBT‐C ceramic (∼60 pC/N). Accordingly, a large improvement in piezoelectric voltage coefficient (g33) of almost 300% in poled KBT‐R (∼45 × 10−3 Vm/N) and 400% in KBT‐P (∼54 × 10−3 Vm/N) samples over the KBT‐C ceramic was obtained. Interestingly, a significantly lower activation energy (Ea) for KBT‐C (∼0.71 eV) below the temperature of the dielectric maximum (Tm) was noticed compared to KBT‐R (∼1.07 eV) and KBT‐P (∼1.00 eV), suggesting a strong dependence of DC conduction on grain morphology. Furthermore, chronoamperometry measurements confirmed a mixed electronic and ionic conduction at higher temperatures in all samples.

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