Abstract
We have measured optical reflectivity of Li- and Ti-doped NiO (LTNO) in the infrared range at various temperatures. A Drude-type absorption is found at low energy, 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 . 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 .
- Received 1 March 2004
- Corrected 13 December 2004
DOI:https://doi.org/10.1103/PhysRevB.70.172106
©2004 American Physical Society
Corrections
13 December 2004