On the dielectric spectroscopy of copper doped layered Na1.6K0.4Ti3O7 ceramics

Maurya, Deepam; Chand, Prem

doi:10.1016/j.jallcom.2007.04.279

Cited by 11 publications

(3 citation statements)

References 27 publications

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“…It is interesting that a large number of titanate nanostructures (i.e., nanotubes, nanowires, and nanobelts) have been widely obtained by a simple hydrothermal treatment of TiO 2 particles in NaOH solution [5,[10][11][12][13][14] since the first report on the successful synthesis of titanate nanotubes [15]. Though the detailed structure of these materials is under debate, it has been generally recognized that many sodium titanate nanomaterials crystallize as layered trititanate structures, suggested to be layers of Na 2 [16][17][18][19][20][21][22]. Due to the high-performance ionexchange property of Na 2 Ti 3 O 7 , it may be used for removal and recovery of heavy metal ions from industrial wastewaters [18], lithium-ion batteries and hydrogen storage materials [5,16].…”

Section: Introductionmentioning

confidence: 99%

First-principle calculations for electronic structure and bonding properties in layered Na2Ti3O7

Xiang

et al. 2011

Open Physics

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Ê Ú ¾¼ Å Ö ¾¼½½ ÔØ ¾ ÂÙÐÝ ¾¼½½ ×ØÖ ØFirst-principles calculations of Na 2 Ti 3 O 7 have been carried out with density-functional theory (DFT) and ultrasoft pseudopotentials. The electronic structure and bonding properties in layered Na 2 Ti 3 O 7 have been studied through calculating band structure, density of states, electron density, electron density difference and Mulliken bond populations. The calculated results reveal that Na 2 Ti 3 O 7 is a semiconductor with an indirect gap and exhibits both ionic and covalent characters. The stability of the (Ti 3 O 7 ) 2− layers is attributed to the covalent bonding of strong interactions between O 2p and Ti 3d orbitals. Furthermore, the O atoms located in the innerlayers interact more strongly with the neighboring Ti atoms than those in the interlayer regions. The ion-exchange property is due to the ionic bonding between the Na + and (Ti 3 O 7 ) 2− layers, which can stabilize the interlayers of layered Na 2 Ti 3 O 7 structure.

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Section: Introductionmentioning

confidence: 99%

First-principle calculations for electronic structure and bonding properties in layered Na2Ti3O7

Xiang

et al. 2011

Open Physics

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“…The material close to the transition temperature shows a positive temperature coefficient of resistivity (PTCR). The grain boundary is closely related to PTCR behavior [30]. The PTCR effect is caused by trapped electrons at the grain boundaries, as explained by the well-established Heyyang model.…”

Section: Resultsmentioning

confidence: 94%

Study of Co-Doped K2Ti6O13 Lead-Free Ceramic for Positive Temperature Coefficient Thermistor Applications

Shariq

Siddiqui²,

Qamar

et al. 2022

Crystals

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Cobalt-doped potassium hexa-titanate (Cox:K2Ti6O13 (x = 0.05, 0.10, 0.15 mole%)) ceramics were synthesized by the solid-state reaction method. The XRD patterns confirmed single-phase development in a monoclinic symmetry of various samples, and they were used for different structural calculations of Cox:K2Ti6O13 ceramics. The dielectric constant, tanδ, electrical modulus, and ac conductivity of Co-doped K2Ti6O13 were studied in the temperature range of 100–500 °C. Anomalies were observed in graphs of the dielectric constant versus temperature, showing the transition phase in the studied samples. Dielectric peaks at transition temperature decreased with an increasing frequency, and the peaks shifted toward higher temperatures, illustrating the relaxation of the dielectric materials. The composition with x = 0.10 showed low dielectric loss and a higher dielectric constant and can be utilized for high-temperature dielectric material. Small doping of cobalt improved the ac conductivity of K2Ti6O13 ceramics due to the increase in the spin–phonon interaction and dominant electron hopping conduction; however, the conductivity diminished with substantial doping because of the contraction of the tunnel space and ambushing of conduction electrons. The uniqueness of this study is in the high dielectric optimization of lead-free ceramic Cox:K2Ti6O13 and the discovery of positive temperature coefficients of the resistivity of these ceramic samples.

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“…And then these excited electrons will be captured and transferred to H + ions. Therefore, the configuration of 3d orbitals actually predicts the electron captureability of a dopant [28,29].…”

Section: Effects Of Cu Dopingmentioning

confidence: 99%