Complex dielectric properties of LuFe2O4

The results of broadband (100 Hz – 1 MHz) dielectric measurements on polycrystalline LuFe2O4 samples from 80 K to 400 K will be presented. The real part of the dielectric constant has been found to decrease gradually as the test frequency increases at all measured temperatures. Similarly, the imaginary part of the dielectric constant also decreases as a function of frequency in contrast to the Debye model. Moreover, the dissipation factor, which is associated with the lossy character of the dielectric material, significantly improves at lower temperatures. Resistivity of LuFe2O4 has shown two distinct activation energies above and below ~310 K, possibly indicating the ferroelectric transition. While LuFe2O4 has been known for its multiferroic property with its colossal dielectric constant, recent dielectric property measurements on LuFe2O4 have revealed contradicting results. Such results are believed to be caused by the space charge effects at the interface between the electrical contacts and the sample, also known as the Maxwell-Wagner effects. As a result, the intrinsic dielectric constant of LuFe2O4 could be strongly influenced by the contact effects. Measured dielectric data have been compared with the published results and analyzed in order to distinguish between the intrinsic and extrinsic components of the dielectric properties.