High dielectric constant in Al-doped ZnO ceramics using high-pressure treated powders

Realistic dielectric response of high temperature sintered ZnO ceramic: a microscopic and spectroscopic approach

“…Three-dimensional pockets of the voids around the grain boundaries offer high surface area to the defects to be distributed and damage the conduction path of the charge carriers thereby increasing resistance to the transport of charge carriers. 48,50 For ZnO-1400 sample, we observe reduction in the values of R GB2 , which is suggested due to conversion of open voids to close voids due to grain growth as shown by Fig. 3(c).…”

“…In ZnO and other ceramic oxides, the grain boundary resistance is generally higher in comparison to the grains due to segregation of point defects (i.e., oxygen vacancies, zinc interstitial and zinc vacancies) at grain boundaries. [47][48][49] In addition, voids exist in the form of three-dimensional pockets around the grain boundaries. The high surface area of the voids provides chance for the defects to be distributed and creates obstruction to the ow of charge carriers by reducing the conduction path and compressing current lines, analogous to the effect of impurities at grain boundaries.…”

“…The high surface area of the voids provides chance for the defects to be distributed and creates obstruction to the ow of charge carriers by reducing the conduction path and compressing current lines, analogous to the effect of impurities at grain boundaries. 48,50 A relationship of the two commonly observed features (small and large semicircular arcs) has been made based on the magnitudes of the associated capacitances. Thus; the high frequency arc is endorsed to the bulk response and the low frequency arc to grain boundary impedance.…”

Low-temperature synthesis of Ti3Al(Sn)C2 solid solution using replacement reaction

“…Figure 1a shows the comparison of peak positions before and after Sn-replaced Ti 3 AlC 2 . Compared with Ti 3 AlC 2 , the XRD peaks after adding Sn are shifted towards lower angles, such as (103), (104), and (105) peaks, which may be caused by the replacement of Al atoms by Sn atoms [15,24]. The peak strengths of (002), (004), and (006) peaks increased while that (100) peaks decreased, showing the periodic symmetry along the c-axis and the corresponding structural factors can be changed by replacing the atoms in the A layer.…”

“…In order to meet the requirements of high-temperature and high-irradiation special environmental conditions, replacement methods are usually used to improve the properties of the MAX phase [8][9][10][11][12][13][14][15][16]. Tian et al found that the Vickers hardness of (Cr 1-x V x ) 2-AlC (x = 0, 0.1, 0.25, and 0.5) solid solution increased linearly with the increase of the amount of V introduced [9].…”