P. Lunkenheimer

Origin of apparent colossal dielectric constants

Experimental evidence is provided that colossal dielectric constants, epsilon>= 1000, sometimes reported to exist in a broad temperature range, can often be explained by Maxwell-Wagner type contributions of depletion layers at the interface between sample and contacts, or at grain boundaries. We demonstrate this on a variety of different materials. We speculate that the largest intrinsic dielectric constant observed so far in non-ferroelectric materials is of order 100.

Nonintrinsic origin of the colossal dielectric constants in Ca Cu 3 Ti 4 O 12

The dielectric properties of

Relaxor ferroelectricity and colossal magnetocapacitive coupling in ferromagnetic CdCr2S4

\mathrm{Ca}{\mathrm{Cu}}_{3}{\mathrm{Ti}}_{4}{\mathrm{O}}_{12}

Colossal dielectric constants in transition-metal oxides

, a material showing colossal values of the dielectric constant, were investigated over a broad temperature and frequency range extending up to

Excess wing in the dielectric loss of glass formers: A johari-goldstein beta relaxation?

1.3\phantom{\rule{0.3em}{0ex}}\mathrm{GHz}

Relaxation dynamics in plastic crystals

. A detailed equivalent-circuit analysis of the results and two crucial experiments, employing different types of contacts and varying the sample thickness were performed. The results provide clear evidence that the apparently high values of the dielectric constant in

Nature and properties of the Johari–Goldstein β-relaxation in the equilibrium liquid state of a class of glass-formers

\mathrm{Ca}{\mathrm{Cu}}_{3}{\mathrm{Ti}}_{4}{\mathrm{O}}_{12}

Colossal dielectric constants in single-crystalline and ceramic CaCu3Ti4O12 investigated by broadband dielectric spectroscopy

are nonintrinsic and due to electrode polarization effects. The intrinsic properties of

Glassy Aging Dynamics

\mathrm{Ca}{\mathrm{Cu}}_{3}{\mathrm{Ti}}_{4}{\mathrm{O}}_{12}

Broadband dielectric spectroscopy on single-crystalline and ceramic CaCu3Ti4O12

are characterized by charge transport via hopping of localized charge carriers and a relatively high dielectric constant of the order of 100.