title: Origin of constant loss in ionic conductors.
abstract: We have analyzed the constant loss contribution to the ac conductivity in the frequency range 10 Hz-1 MHz and temperatures down to 8 K, for two Li ionic conductors, one crystalline (Li(0.18)La(0.61)TiO(3)) and the other glassy (61SiO(2);35Li(2)O.3Al(2)O3.P(2)O(5)). As temperature is increased a crossover is observed from a nearly constant loss to a fractional power law frequency dependence of the ac conductivity. At any fixed frequency omega, this crossover occurs at a temperature T such that omega approximately nu(0)exp(-E(m)/k(B)T), where nu(0) is the attempt frequency and E(m) is identified with the barrier for Li+ ions to leave their wells.
authors.affiliation: Naval Research Laboratory, Washington, D.C. 20375-5320, USA.
authors.forename: C
authors.initials: C
authors.lastname: León
authors.forename: A
authors.initials: A
authors.lastname: Rivera
authors.forename: A
authors.initials: A
authors.lastname: Várez
authors.forename: J
authors.initials: J
authors.lastname: Sanz
authors.forename: J
authors.initials: J
authors.lastname: Santamaria
authors.forename: K L
authors.initials: KL
authors.lastname: Ngai