Dielectric properties of charge ordered LuFe2O4 revisited: The apparent influence of contacts

TL;DR

This study investigates the dielectric properties of LuFe2O4, revealing that its apparent ferroelectric behavior is likely due to contact effects rather than intrinsic polarization, challenging previous assumptions about its multiferroic nature.

Contribution

The paper provides a detailed broadband dielectric analysis showing that contact effects dominate the dielectric response, questioning the intrinsic ferroelectricity of LuFe2O4.

Findings

Dielectric response explained by Maxwell-Wagner effects and hopping conductivity.

No evidence of intrinsic dipolar polarization in LuFe2O4.

Contact effects significantly influence the dielectric measurements.

Abstract

We show results of broadband dielectric measurements on the charge ordered, proposed to be mul- tiferroic material LuFe2O4. The temperature and frequency dependence of the complex permittivity as investigated for temperatures above and below the charge-oder 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 LuFe2O4 has to be questioned.