Grain size dependence of relaxor behavior in CaCu3Ti4O12 ceramics

Abstract

The dielectric properties show a typical ferroelectric relaxor behavior in CaCu3Ti4O12 ceramics with different grain sizes in the temperature range of 400–600K. The relaxation strength and the frequency dispersion increase with grain size decreasing, which can be due to the different stresses in grains with different sizes. These variations have been confirmed by the modified Curie-Weiss law. The results fitted well by the Volgel-Fulcher relationship and the variations in the slim current-voltage loops are correlated with the microstructures closely. It can be proposed that the grain size is one of the main factors of affecting the relaxor behavior.

Dielectric relaxation of high-k oxides

“…The smaller the grain size, the more intense is the dielectric relaxation. These findings are in good agreement with the theoretical and experimental studies proposed by Yu et al [86], which reported the effect of grain size on the ferroelectric relaxor behavior in CaCu 3 TiO 12 (CCTO) ceramics (shown in inset of Figure 9b). The dielectric relaxation for the small grain size sample is the worst.…”

Dielectric properties of the Ca1−xLaxCu3Ti4−xCoxO12 system (x=0.10, 0.20 and 0.30) synthesized by semi-wet route

“…It is observed that the broadening of peaks show a typical relaxer behavior. These peaks shift to low frequency with decreasing temperature [21]. The resonance effect is also clear at high frequency and at different temperatures which is shown in the inset of the figure.…”

Extrinsic and Intrinsic Frequency Dispersion of High-k Materials in Capacitance-Voltage Measurements

“…Three possible causes of the dielectric relaxation for the La x Zr 1−x O 2−δ dielectric are possible: (1) ion movement of unbounded La + or Zr + ions in the metal-oxide lattice resulting in dielectric relaxation [83]; (2) the combination of unbound metal ions with electron traps, generating dipole moments and inducing dielectric relaxation [84]; (3) a decrease in crystal grain size, causing an increase in the dielectric relaxation due to increased stresses [85,86]. It has been shown that the effect of the cation segregation caused by annealing and rapped electrons on the dielectric relaxation were negligible [26].…”