Relaxor-Like Dielectric Relaxation: Artifacts and Intrinsic Properties

Annealing effects, anomalous dielectric properties and conductivity of As-diluted lead phosphate Pb3(P1–xAsxO4)2

“…Such anomalies are qualitatively similar to those observed in perovskite-type crystals [3][4][5][14][15][16][17]. In general these anomalies can be due to complex dispersion phenomena in the bulk of the crystals [3-5, 15, 17] as well as to artefacts such as space charge relaxations in the crystal-electrode interface or disturbed layers close to the crystal surface [14,16,18]. The high-temperature anomalous dielectric behaviour in perovskites has also been explained in terms of superparaelectric clusters existing at high temperatures [15] or a temperature dependent distribution of the hopping times of mobile charge carriers [17].…”

“…The parameters from fits of Eq. (11)(12)(13)(14)(15)(16)(17)(18) to the temperature dependencies of the real part of the dielectric permittivity and conductivity for as-grown and annealed in wet argon samples. K, S Á K/m Á s 5Á 10 À8 9 Á 10 À8 3 Á 10 À9 7 Á 10 À9 5 Á 10 À9…”

“…Figure 3 shows fits of the experimental dependencies of e 0 ðw; TÞ on heating using Eqs. (11)(12)(13)(14)(15)(16)(17)(18) for crystals with x ¼ 0.52. It can be seen that there is close agreement between experimental and calculated dependencies for different frequencies.…”

High‐Temperature Dielectric Relaxation in Pb(Mg1/3Nb2/3)O3–PbTiO3 Single Crystals

“…To date, several mechanisms have been proposed to interpret the pseudo‐relaxor behavior. These mechanisms can be classified into five types: (1) the dipole model associated with different mobile defects based on the universal feature that the anomaly is very sensitive to the oxygen vacancy especially for the titanate perovskites; (2) the Maxwell‐Wagner (MW) model due to electrical inhomogeneity in the tested sample; (3) the competitive phenomenon between the dielectric relaxation and the electric conduction of the relaxing species; (4) electronic ferroelectrics due to electrons hopping between polyvalent states of transition‐metal ions; and (5) an artificial phenomenon resulting from the negative capacitance . Our recent work on the pseudo‐relaxor anomaly in CaCu 3 Ti 4 O 12 revealed that the anomaly is composed of two types of relaxations with the low‐temperature relaxation being the dipolar relaxation and the high‐temperature relaxation being the MW relaxation.…”

Diffuse Dielectric Anomalies in CoTiO3 at High Temperatures

“…To date, several mechanisms unrelated to true relaxor that can produce a relaxor-like anomaly have been proposed. These mechanisms can be classified into three types: (i) the dipole model associated with different mobile defects based on the universal feature that the anomaly is very sensitive to the oxygen vacancy especially for the titanate perovskites [13][14][15]; (ii) the Maxwell-Wagner model due to electrical inhomogeneity in the tested sample [16][17][18][19]; and (iii) the competitive phenomenon between the dielectric relaxation and the electric conduction of the relaxing species [20][21][22]. Before clarifying which mechanism underlies the observed anomalies, details about the nature of these anomalies are required.…”