How Electrons Become Mobile in a Colossal Dielectric -- Fe2TiO5
Abstract
We measure the colossal permittivity in single crystal Fe2TiO5 using broadband spectroscopy in the frequency range 20 Hz - 1 MHz. The relaxation response is analyzed using a Debye-like model with Arrhenius activation in two different ways and yields an energy barrier of 286.1 2.8 meV. DC transport yields an activation energy of 288.8 2.8 meV. These results strongly imply that the energy barrier for localized dipole motion and itinerant charge transport originate from the same atom-level forces. A further implication is that colossal dielectric behavior is a microscopic bulk phenomenon arising from a system on brink of metallicity.
0