title: Kinetics of the charge ordering in magnetite below the Verwey temperature.
abstract: In this work the kinetics of the charge ordering in magnetite (Fe3O4) below the Verwey transition temperature TV is investigated in time and energy domain. After excitation by a one-second voltage pulse to destruct the charge-ordered state below TV, an alternating current (AC) is used to perturb its recovery process. Upon warming up to above a temperature T(r)(< TV) the charge order recovers despite the ac perturbation, because the temperature-dependent relaxation time becomes shorter than the polarity change of the ac. From the frequency dependence of T(r)(f), an activation energy of ΔE = 126 meV is extracted. Below Tr the real part of the ac conductance Greal follows the relation Greal ∼ f(α) with α = 0.98 ± 0.18, suggesting that the charge reordering is driven by correlated hopping transport. The relaxation time τ = 1/f(T(r)) of the charge-ordered state is determined for temperatures between 70 and 98 K and is extrapolated to τ(TV) = 1.6 ms, continuously slowing down its dynamics as the temperature is decreased.
authors.affiliation: Institute of Applied Physics, Universität Hamburg, Jungiusstrasse 11, 20355 Hamburg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Gooth
authors.forename: Tim
authors.initials: T
authors.lastname: Böhnert
authors.forename: Jan G
authors.initials: JG
authors.lastname: Gluschke
authors.forename: Bacel
authors.initials: B
authors.lastname: Hamdou
authors.forename: Sven
authors.initials: S
authors.lastname: Barth
authors.forename: Detlef
authors.initials: D
authors.lastname: Görlitz
authors.forename: Robert
authors.initials: R
authors.lastname: Zierold
authors.forename: Kornelius
authors.initials: K
authors.lastname: Nielsch