K2(NbO)2Si4O12: a new ferroelectric

Foster, M. C.; Arbogast, D. J.; Photinos, Panos; Nielson, R. M.; Abrahams, S. C.

doi:10.1107/s0021889898016501

Cited by 6 publications

(7 citation statements)

References 8 publications

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“…The estimated P s value was substantially lower than the previously-reported value of 5¯C/cm 2 for KNbSi 2 O 7 ceramics. 1) On the other hand, the estimated E c value was considerably higher than the previously-reported value of 0.7 kV/cm. These results suggested that the low P s value for KNbSi 2 O 7 single crystal is caused by the difficulty in polarization switching of single domain state due to the high coercive field.…”

Section: Resultscontrasting

confidence: 65%

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Fabrication of ferroelectric silicate KNbSi2O7 single crystal

Sahashi

Hoshina

Takeda

et al. 2014

J. Ceram. Soc. Japan

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ABSi 2 O 7 is a new ferroelectric material group of which ferroelectricity has been discovered recently. In this study, we focused on potassium niobate silicate (KNbSi 2 O 7 ), which comprises displacement-type ferroelectric substance KNbO 3 and high-covalence substance SiO 2 in the structure. KNbSi 2 O 7 single crystals with a size of 10 © 10 © 1 mm 3 were fabricated by the process of glass crystallization, re-melting, and slow-cooling. The polarization-electric field (P-E) curve of the KNbSi 2 O 7 crystal was evaluated and KNbSi 2 O 7 evidently showed ferroelectricity in the direction of c axis. The value of the spontaneous polarization was estimated to 0.11¯C/cm 2 . The dielectric permittivity was approximately 15 for both a and c axes at 1 MHz, and this material was found to be a ferroelectric material with low dielectric permittivity.

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Section: Resultscontrasting

confidence: 65%

“…4) They fabricated KNbSi 2 O 7 polycrystalline ceramics and measured the polarization-electric field (P-E) hysteresis of the ceramics. The anisotropies of dielectric and ferroelectric properties of KNbSi 2 O 7 remain unclear.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of ferroelectric silicate KNbSi2O7 single crystal

Sahashi

Hoshina

Takeda

et al. 2014

J. Ceram. Soc. Japan

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“…The natural analog of the tetragonal synthetic phase KNbSi 2 O 7 , a new structural type among natural K-Nb-cyclosilicates, named rippite, was discovered in calciocarbonatites of the Chuktukon massif, Chadobets upland, SW Siberian Platform, Krasnoyarsk Territory, Russia [ [4]. It is rather inert and chemically stable and is not dissolved in inorganic acids except HF.…”

Section: Introductionmentioning

confidence: 99%

“…It is rather inert and chemically stable and is not dissolved in inorganic acids except HF. All studies on KNbSi 2 O 7 are mainly focused on its nonlinear optical property [3][4][5][6][7][8][9][10][11][12][13][14][15]. Single crystals, ceramics, glass-ceramics, and glass of KNbSi 2 O 7 and similar compositions in the systems SiO 2 (±GeO 2 )-Nb 2 O 5 -K 2 O have been fabricated [3][4][5][6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

“…All studies on KNbSi 2 O 7 are mainly focused on its nonlinear optical property [3][4][5][6][7][8][9][10][11][12][13][14][15]. Single crystals, ceramics, glass-ceramics, and glass of KNbSi 2 O 7 and similar compositions in the systems SiO 2 (±GeO 2 )-Nb 2 O 5 -K 2 O have been fabricated [3][4][5][6][7][8][9][10][11][12]. The synthesis of glasses and glass-ceramics in the system SiO 2 -Nb 2 O 5 -K 2 O has shown that K 2 Nb 2 (Si 4 O 12 )O 2 may be appeared in the 510-735 • C temperature range in glass/melt [4,6,[8][9][10]13,14].…”

Section: Introductionmentioning

confidence: 99%

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Rippite, K2(Nb,Ti)2(Si4O12)O(O,F), a New K-Nb-Cyclosilicate from Chuktukon Carbonatite Massif, Chadobets Upland, Krasnoyarsk Territory, Russia

et al. 2020

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Rippite K2(Nb,Ti)2(Si4O12)(O,F)2, a new K-Nb-cyclosilicate, has been discovered in calciocarbonatites from the Chuktukon massif (Chadobets upland, SW Siberian Platform, Krasnoyarsk Territory, Russia). It was found in a primary mineral assemblage, which also includes calcite, fluorcalciopyrochlore, tainiolite, fluorapatite, fluorite, Nb-rich rutile, olekminskite, K-feldspar, Fe-Mn–dolomite and quartz. Goethite, francolite (Sr-rich carbonate–fluorapatite) and psilomelane (romanèchite ± hollandite) aggregates as well as barite, monazite-(Ce), parisite-(Ce), synchysite-(Ce) and Sr-Ba-Pb-rich keno-/hydropyrochlore are related to a stage of metasomatic (hydrothermal) alteration of carbonatites. The calcite–dolomite coexistence assumes crystallization temperature near 837 °C for the primary carbonatite paragenesis. Rippite is tetragonal: P4bm, a = 8.73885(16), c = 8.1277(2) Å, V = 620.69(2) Å3, Z = 2. It is closely identical in the structure and cell parameters to synthetic K2Nb2(Si4O12)O2 (or KNbSi2O7). Similar to synthetic phase, the mineral has nonlinear properties. Some optical and physical properties for rippite are: colorless; Mohs’ hardness—4–5; cleavage—(001) very perfect, (100) perfect to distinct; density (meas.)—3.17(2) g/cm3; density (calc.)—3.198 g/cm3; optically uniaxial (+); ω = 1.737-1.739; ε = 1.747 (589 nm). The empirical formula of the holotype rippite (mean of 120 analyses) is K2(Nb1.90Ti0.09Zr0.01)[Si4O12](O1.78OH0.12F0.10). Majority of rippite prismatic crystals are weakly zoned and show Ti-poor composition K2(Nb1.93Ti0.05Zr0.02)[Si4O12](O1.93F0.07). Raman and IR spectroscopy, and SIMS data indicate very low H2O content (0.09–0.23 wt %). Some grains may contain an outermost zone, which is enriched in Ti (+Zr) and F, up to K2(Nb1.67Ti0.32Zr0.01)[Si4O12](O1.67F0.33). It strongly suggests the incorporation of (Ti,Zr) and F in the structure of rippite via the isomorphism Nb5+ + O2− → (Ti,Zr)4+ + F1−. The content of a hypothetical end-member K2Ti2[Si4O12]F2 may be up to 17 mol. %. Rippite represents a new structural type among [Si4O12]-cyclosilicates because of specific type of connection of the octahedral chains and [Si4O12]8− rings. In structural and chemical aspects it seems to be in close with the labuntsovite-supergroup minerals, namely with vuoriyarvite-(K), K2(Nb,Ti)2(Si4O12)(O,OH)2∙4H2O.

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Candidate ferroelectrics via ab initio high-throughput screening of polar materials

Ricci,

Reyes-Lillo,

Mack

et al. 2024

npj Comput Mater

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Ferroelectrics are a class of polar and switchable functional materials with diverse applications, from microelectronics to energy conversion. Computational searches for new ferroelectric materials have been constrained by accurate prediction of the polarization and switchability with electric field, properties that, in principle, require a comparison with a nonpolar phase whose atomic-scale unit cell is continuously deformable from the polar ground state. For most polar materials, such a higher-symmetry nonpolar phase does not exist or is unknown. Here, we introduce a general high-throughput workflow that screens polar materials as potential ferroelectrics. We demonstrate our workflow on 1978 polar structures in the Materials Project database, for which we automatically generate a nonpolar reference structure using pseudosymmetries, and then compute the polarization difference and energy barrier between polar and nonpolar phases, comparing the predicted values to known ferroelectrics. Focusing on a subset of 182 potential ferroelectrics, we implement a systematic ranking strategy that prioritizes candidates with large polarization and small polar-nonpolar energy differences. To assess stability and synthesizability, we combine information including the computed formation energy above the convex hull, the Inorganic Crystal Structure Database id number, a previously reported machine learning-based synthesizability score, and ab initio phonon band structures. To distinguish between previously reported ferroelectrics, materials known for alternative applications, and lesser-known materials, we combine this ranking with a survey of the existing literature on these candidates through Google Scholar and Scopus databases, revealing ~130 promising materials uninvestigated as ferroelectric. Our workflow and large-scale high-throughput screening lays the groundwork for the discovery of novel ferroelectrics, revealing numerous candidates materials for future experimental and theoretical endeavors.

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K₂(NbO)₂Si₄O₁₂: a new ferroelectric

Cited by 6 publications

References 8 publications

Fabrication of ferroelectric silicate KNbSi<sub>2</sub>O<sub>7</sub> single crystal

Fabrication of ferroelectric silicate KNbSi<sub>2</sub>O<sub>7</sub> single crystal

Rippite, K2(Nb,Ti)2(Si4O12)O(O,F), a New K-Nb-Cyclosilicate from Chuktukon Carbonatite Massif, Chadobets Upland, Krasnoyarsk Territory, Russia

Candidate ferroelectrics via ab initio high-throughput screening of polar materials

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