Speaker
Susan Yee
Description
In $+$ Nb co-doped TiO$_2$ has been previously investigated and shown to display colossal permittivity ($\epsilon_1 >10^3$) for frequencies less than or equal to 1 MHz using impedance spectroscopy. In this work the lattice vibrational contribution to the low frequency dielectric function is studied in ceramic samples at the 0\%,5\%, and 10\% doping level using temperature-dependent reflectance spectroscopy. It is found that the soft mode behaviour exhibited by the lowest frequency infrared ibrational mode in pure TiO$_2$ is not strongly affected by the co-doping. There is a large discrepancy between the $\epsilon_1$ measured at the lowest far infrared frequencies in this reflectance spectroscopy study ($\approx 1.5$ THz) and the value measured below 1 MHz.
Authors
David Crandles
(Brock University)
Susan Yee
