We report on the temperature and magnetic-field dependence of dielectric constant ε 1 c and conductivity σ 1 calong the c axis in the antiferromagnetic insulating (AFM-I) state of λ-(BEDT-TSF) 2FeCl 4, which indicate some dielectric ordering in coexistence with AFM-I. There appears a sharp upturn of saturated electric polarizations and a colossal magnetodielectricity (CMD) in magnetic fields. On a basis of the π-d superexchange interaction we propose a charge ordering-induced polarization model leading to two candidates of ferroelectric or antiferroelectric orderings, and discuss the prominent magnetoelectric effects associated with CMD in terms of the field-induced unlocking or melting charge ordering.
|ジャーナル||Physical Review B - Condensed Matter and Materials Physics|
|出版ステータス||Published - 2005 1月|
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