Infrared study of giant dielectric constant in Li- and Ti-doped NiO

Abstract

We have measured optical reflectivity of Li and Ti doped NiO (LTNO) in the infrared range at various temperatures. A Drude-like absorption is found at low energy, ω < 100 cm −1 and its spectral weight increases substantially as temperature decreases. This observation and DC-resistivity result show that LTNO has a conductive grain and resistive boundary. Such composite structure provides evidence of the Maxwell-Wagner (MW) mechanism as the origin of the high dielectric constant εo. We propose a three-phase granular structure and show that this extended MW model explains the observed frequency and temperature dependence of the dielectric constant as well as the giant value of εo.

Giant dielectric response and relaxation behavior of Bi3+/W6+ co-doped TiO2 ceramics

“…The design and development of CP materials with high dielectric constant (>10 3 ) and low loss tangent (<10 −1 ), as well as high thermal stability for high-end ceramic capacitors has become a current hot research area. A range of promising CP materials have been intensively studied, such as NiO, 1,2 ferroelectrics, 3–5 CaCu 3 Ti 4 O 12 (CCTO), 6,7 ACu 3 Ti 4 O 12 (ACTO), 8,9 etc. Unfortunately, their practical application in the electronics industry is restricted owing to large tan δ , strong frequency/temperature dependence of ε r , low phase transition temperature, and potential environmental contamination/or other factors.…”

Computational and experimental investigations of the giant dielectric property of Na1/2Y1/2Cu3Ti4O12 ceramics

“…Previously published studies indicated that the performance of capacitors is enhanced since their use is critical for temporary electric storage [1][2][3][4][5] . Ceramic capacitors are widely used as essential components in a variety of devices, such as graphics cards and random-access memory (RAM) 13 . The dielectric properties of a material determine its suitability for various applications, especially for capacitors.…”