Effects of DC bias on non-ohmic sample-electrode contact and grain boundary responses in giant-permittivity La_1.7Sr_0.3Ni_1−xMg_xO₄ ceramics

Abstract

The effects of DC bias on the giant dielectric properties and electrical responses of non-ohmic sample-electrode contact and grain boundaries of La1.7Sr0.3Ni1−xMgxO4 (x = 0–0.5) ceramics were studied.

Origin(s) of the apparent colossal permittivity in (In1/2Nb1/2)xTi1−xO2: clarification on the strongly induced Maxwell–Wagner polarization relaxation by DC bias

“…Concurrently, DC bias also can cause a decrease in the amount of accumulated charges, which leads to a decrease in the intensity of Maxwell-Wagner polarization and 3 0 . 22,23 For CuO and La 2Àx Sr x NiO 4 ceramics, in which their colossal dielectric responses are dominated by the non-ohmic sample-electrode effect, 22,24 the low-frequency 3 0 values at room temperature (RT) can easily be reduced by applying DC bias at 0-4 and 0-1.5 V, respectively. The low-frequency 3 0 value (at 200 C) caused by the sampleelectrode effect for a CCTO ceramic was decreased by applying DC bias at 0-2 V. 21 For the effect of DC bias on the GB response in CCTO ceramics, variations in their dielectric and electrical properties are dependent on their microstructures (e.g., mean grain size and grain size distribution).…”

“…The effects of DC bias on the electrical response of the sample-electrode contact and associated colossal dielectric properties of the 2.5% N-T ceramic are similar to those observed in other colossal dielectric materials such as CuO, CCTO and La 2Àx Sr x NiO 4 ceramics. 21,22,24 It is notable that the relaxation frequency of the tan d peak did not change [inset of Fig. 6(a)].…”

Greatly enhanced dielectric permittivity in La1.7Sr0.3NiO4/poly(vinylidene fluoride) nanocomposites that retained a low loss tangent

“…The extremely large 3 0 value of LSNO was intrinsically attributed to a small polaronic hopping mechanism in the grain interiors or inside particles. 23,[25][26][27] Therefore, such a large 3 0 value is usually accompanied by large values of tan d and DC conductivity, as shown in the inset of Fig. 5.…”

“…23 The origin of the giant dielectric response in La 2Àx Sr x NiO 4 ceramics was intrinsically caused by the adiabatic small polaronic hopping process of Ni 2+ and Ni 3+ . [24][25][26][27] Therefore, La 2Àx Sr x NiO 4 is an important candidate for making high 3 0 exible polymeric composites for various applications. Unfortunately, to our best knowledge, this highpermittivity La 2Àx Sr x NiO 4 ceramic has rarely been incorporated into a PVDF polymer to enhance its 3 0 value.…”

Transition‐Metal Dichalcogenide NiTe2: An Ambient‐Stable Material for Catalysis and Nanoelectronics

“…The doublet is practically unchanged upon CO exposure, while H 2 O adsorption attenuates the signal by 60%. Following O 2 exposure, the intensity of the Ni‐3p level is reduced by 42% with the emergence of a new doublet with a J = 3/2 component at 67.6 eV, which is associated with Ni(II) species, [ 22 ] evidently related to NiO bonds. The intensity of this doublet is, however, just 11% of the total area of the Ni‐3p signal.…”