Dielectric characteristic of nanocrystalline Na0.5K0.5NbO3 ceramic green body

Abstract

Dielectric spectroscopy was applied to porous nanocrystalline Na 0.5 K 0.5 NbO 3 (NKN) ceramic green body, wherein influences of percolation effect and water adsorption at pore surface of the ceramic green body on dielectric response were examined over wide temperature (150 to 450 K) and frequency (100 Hz to 1 MHz) ranges. Dielectric permittivity of the ceramic green body is about 2-3 orders of magnitude higher than that of pure NKN powder or NKN ceramic. Furthermore, the high dielectric permittivity and high humidity sensitivity of the ceramic green body can appear again with aging a period of time in air. The data from this investigation make potential applications for NKN as a giant dielectric material or a humidity sensing material.

Interplay between Defects and Cation Nonstoichiometry in Lithium-Substituted CdGa2O4 Leading to Multifunctional Behavior

“…24,25 The dielectric spectroscopic properties of oxides with high alkali metal ion content have been found to be sensitive to moisture. 41 For 60 mol % Li + -substituted sample, the dielectric constant behavior was more or less the same after measuring it by keeping in lab atmosphere for nearly 10 days (Figure S6 in the Supporting Information). The consequences of Li + substitution in terms of ionic conductivity in this system have been investigated over the temperature range of 493−773 K. The variation of conductivity (σ) of CdGa 2.66 O y and Cd 0.40 Li 0.60 Ga 2.66 O y as a function of frequency measured in the presence of oxygen (1 atm) as well as in air is plotted in Figure 8a−c.…”

“…The dielectric constant and dielectric loss for Li + -substituted sample were higher, viz., 12.65 and 0.14 (tan δ) compared to the values noted for nonstoichiometric spinel (10.68 and 0.09 (tan δ), respectively). All of these changes were attributed to the creation of oxygen vacancies by Li + substitution altering the polarization behavior. , The dielectric spectroscopic properties of oxides with high alkali metal ion content have been found to be sensitive to moisture . For 60 mol % Li + -substituted sample, the dielectric constant behavior was more or less the same after measuring it by keeping in lab atmosphere for nearly 10 days (Figure S6 in the Supporting Information).…”

Enhanced optical transmittance and energy‐storage performance in NaNbO3‐modified Bi0.5Na0.5TiO3 ceramics

“…However, the dielectric loss tan δ remains an ultralow value below 200°C for all samples, which is beneficial for the energy‐storage ability. For x = 0.5 sample, the high dielectric loss at low temperature is attributed to the water molecular interference 30,31 …”

“…For x = 0.5 sample, the high dielectric loss at low temperature is attributed to the water molecular interference. 30,31 The P-E loops of BNT-xNN ceramics measured under 100 kV/cm at RT are shown in Figure 5a. The slanted and slim P-E loops demonstrate that the ceramics are relaxor ferroelectrics and suitable for applications as energy-storage capacitors.…”

Two-dimensional ultra-thin nanosheets optimize the surface reaction dynamics and photo/pyro-generated carrier transfer of NaNbO3 for an efficient pyro-photo-electric catalytic system

“…The stability of the photoelectrode in the electrolyte is also very important for the practical application of the photoelectrode. 54,55 Therefore, under simulated sunlight, the stability of the photoelectrode was studied. As shown in Fig.…”