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J. Gooth, T. Böhnert, J. Gluschke, B. Hamdou, S. Barth, D. Goerlitz, R. Zierold, K. Nielsch:
"Kinetics of the charge ordering in magnetite below the Verwey temperature";
Journal of Physics: Condensed Matter, 26 (2014), 47; 472202 - 472206.

In this work the kinetics of the charge ordering in magnetite (Fe₃O₄) below the Verwey transition temperature T_V is investigated in time and energy domain. After excitation by a one-second voltage pulse to destruct the charge-ordered state below T_V, an alternating current (AC) is used to perturb its recovery process. Upon warming up to above a temperature T_r(< T_V) 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 T_r the real part of the ac conductance G_real follows the relation G_real ∼ 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 98K and is extrapolated to τ(T_V) = 1.6 ms, continuously slowing down its dynamics as the temperature is decreased.

http://dx.doi.org/10.1088/0953-8984/26/47/472202