title: Dielectric properties of charge-ordered LuFe(2)O(4) revisited: the apparent influence of contacts.
abstract: We show results of broadband dielectric measurements on the charge ordered, proposed to be multiferroic material LuFe(2)O(4). The temperature and frequency dependence of the complex permittivity as investigated for temperatures above and below the charge-order transition near T(CO)≈320  K and for frequencies up to 1 GHz can be well described by a standard equivalent-circuit model considering Maxwell-Wagner-type contacts and hopping induced ac conductivity. No pronounced contribution of intrinsic dipolar polarization could be found, and thus the ferroelectric character of the charge order in LuFe(2)O(4) has to be questioned.
authors.affiliation: II. Physikalisches Institut, Universität zu Köln, D-50937 Köln, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Niermann
authors.forename: F
authors.initials: F
authors.lastname: Waschkowski
authors.forename: J
authors.initials: J
authors.lastname: de Groot
authors.forename: M
authors.initials: M
authors.lastname: Angst
authors.forename: J
authors.initials: J
authors.lastname: Hemberger