Dielectric, AC-impedance, modulus studies on 0.5BaTiO3·0.5CaCu3Ti4O12 nano-composite ceramic synthesized by one-pot, glycine-assisted nitrate-gel route

A novel low cost non-aqueous chemical route for giant dielectric constant CaCu3Ti4O12 ceramic

“…The characteristics of this ceramic indicate the potential applications in the fields of microelectronics and memory devices, such as static and dynamic random access memory. Unfortunately, the tan d value of CCTO ceramic was found to be greater than 0.05 at room temperature and a frequency of 10 3 Hz [7], which limits the use of this, ceramic commercially. The origin of the high dielectric constant in CCTO ceramics have been properly established.…”

Low temperature sintered giant dielectric permittivity CaCu3Ti4O12 sol-gel synthesized nanoparticle capacitors

“…Modulus analysis of these ceramics confirms the presence of temperature-dependent MW polarization relaxation mechanism at all measured temperatures and frequencies. 35 From complex electric modulus plots, a single semicircular arc is observed at high frequency followed by a straight line tail at low frequency at all measured temperatures. This semicircular arc at high frequency is attributed to bulk or grain part of the material, which shows the capacitance contribution.…”

“…This leads to hopping of electrons among the two different valence states, which increases the conductivity of the grains. [35][36][37] However, in case of stoichiometric CCTO, the conduction mechanism is attributed to the hopping of the charge carriers between the Cu 2þ and Cu 3þ . 29 …”

“…9 According to Kr€ oger-Vink defect notation, during sintering process, oxygen vacancies were formed due to loss of the oxygen. 35,36 Upon cooling, insulating grain boundaries re-oxidize faster (grain boundary diffusion) than that of semiconducting grain V. S. Puli et al J. Adv. Dielect.…”

“…This linear increase in ac relates to the electrical conduction by electron exchange between (Cu þ2 $ Cu þ1 Þ the Cu ions with different valence (Cu þ2 and Cu þ1 ) states. [35][36][37] The electrons released in the above reaction were captured by the Cu þ2 to form Cu þ1 (Cuþ). This leads to hopping of electrons among the two different valence states, which increases the conductivity of the grains.…”