Dielectric, modulus and impedance spectroscopic studies of nanostructured CaCu2.70Mg0.30Ti4O12 electro-ceramic synthesized by modified sol–gel route

An Overview on Recent Developments in the Synthesis, Characterization and Properties of High Dielectric Constant Calcium Copper Titanate Nano-Particles

“…Xu et al [45] prepared Zn-substituted CaCu 3 Ti 4 O 12 ceramics by the sol-gel method using the precursors of Ca(CH 3 COO) 2 ·H 2 O, 4 O 12 (the sample with x = 0.06) had the best properties, with the highest nonlinear coefficient, the lowest threshold field, a high dielectric constant and a low dielectric loss factor at frequencies below 10 5 Hz. These properties make it a candidate for applications in low voltage varistor switchings, gassensing devices and varistor-capacitor double property devices.…”

“…Dielectric materials can be used to store electrical energy in the form of charge separation when the electron distributions around constituent atoms or molecules are polarized by an external electric field. Requirement of an ideal capacitor material is that it should have (1) high dielectric constant (10 4 - 10 6 )(2) low dielectric loss (tan δ= 0.01-0.0001) (3) high thermal stability (stable up to 500˚C) and (4)no variation in dielectric constant with temperature and frequency of current in any region.Calcium copper titanate is a member of an oxide family whose general formula is ACu 3 Ti 4 O 12. Depending on different values of a one can get different isomorphs of this family.…”

“…It is the mismatch in size and bonding preferences of these two ions and titanium that drive the large octahedral tilting distortion. ACu 3 [PLZT], which are not environmentally friendly as capacitor materials (dielectric constant ≈ 1000-20,000) [4]. Problems with BaTiO 3 are that it is a ferroelectric perovskite which is quite unstable and shows phase transitions.…”

“…For this reason, a thermally stable high dielectric constant calcium copper titanate, CaCu 3 Ti 4 O 12 (CCTO), which belongs to ACu 3 Ti 4 O 12 family, first reported by Subramanian et al [5] in the year 2000 is the best choice. The very high dielectric constant (~10 4 ) exhibited by (CCTO), which is nearly constant in the temperature range, 100K to 600K, makes it a promising material which can lead, to many important applications in microelectronics and memory devices as static dielectric constant of a material ultimately decides the degree of miniaturization. It may be widely used in the electronic industries to manufacture electronic components such as multilayer capacitor (MLCC), DRAMs (Dynamic Random Access Memory), microwave devices, electronic devices in automobiles and aircrafts.…”

“…They were characterized by X-ray and TEM techniques and their dielectric properties were studied in the different temperature and frequency regions. Although a large number of papers [19][20][21][22][23] have been published by authors on CCTO where cationic exchange reactions have been studied, in the present paper an overview of the summary of synthesis, characterization by X-rays and dielectric properties for systems giving nano-particles have been reported. In the absence of any review on the CCTO, in general, and CCTO nano-particles in particular, the present paper gives an account of recent development and latest information on calcium copper titanate which will be quite useful for the new workers in this area.…”