Determination of the polarization-depth distribution in poled ferroelectric ceramics using thermal and pressure pulse techniques

Reggi, A.S. De; Dickens, Brian; Ditchi, Thierry; Alquié, C.; Lewiner, J.; Lloyd, Isabel K.

doi:10.1063/1.351306

Cited by 31 publications

(6 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This result is consistent with the injection of positive charge from the wires that are retained in deep traps [8]. The contribution of a polarisation gradient [9] to the effective charge would be expected to give a similar signal but it should decay rapidly as the polarisation relaxed.…”

Section: Space Charge Measurementssupporting

confidence: 75%

Charge injection, electroluminescence, and ageing of an epoxy resin in high divergent fields

Griseri

Fukunaga²,

Laurent³

et al. 2000

Eighth International Conference on Dielectric Materials, Measurements and Applications

View full text Add to dashboard Cite

This is the unspecified version of the paper.This version of the publication may differ from the final published version. Permanent repository link: INTRODUCTIONMost experimental studies of electrical ageing have concentrated on semi-crystalline polymers such as those used in cable insulation and capacitors (see for example [1]). Theoretical models [2][3][4] for electrical ageing have been developed on the basis of these studies. The consensus is that ageing involves the formation of lowdensity regions, though the mechanisms responsible are disputed. For example, bond scission by high-energy electrons [2,5], and mechanical deformation have both been suggested. Both of these mechanisms are related to charge injection and the subsequent formation of high local fields. The semi-crystalline polymers studied so far have similar chemistries and almost identical morphologies. They tend, therefore, to show many similarities in, for example, the size of the energy barriers for the ageing reaction, critical ageing levels, and field dependence of ageing [4]. These similarities make it difficult to discriminate between mechanisms. Epoxy resins, however, are network polymers with a different molecular chemistry to that of the semi-crystalline polymers and are thus ideal to evaluate the proposed ageing mechanisms. We have therefore studied an epoxy resin (CY1301) under both uniform field and high divergent field conditions. Uniform field conditions were used to gain baseline characteristics for the properties of the unaged epoxy resin, and also for the effects of electrical ageing in low fields. Studies in high divergent fields were made using an electrode arrangement adapted from that of [6]. A number of wires set approximately 0.5mm apart were embedded, parallel to the flat faces, in thin (∼290 µm ) flat samples. The radius of the wires ranged from 5 µm (gold plated tungsten) to 25 µm (tungsten). Relatively small voltages applied to the wires (≤5 kV DC) therefore produced local fields up to 170 kV/mm depending upon the wire radius chosen. These field levels are high enough to inject space-charge [6] without leading to instantaneous failure. This geometry, therefore, may both inject charge and simulate local stress enhancements arising from charge accumulation. The number of wires is large (∼30) so that the volume affected is big enough to allow changes on ageing to be detectable. EXPERIMENTAL INVESTIGATIONS Dielectric ResponseThe dielectric response of the epoxy exhibited a glass transition just below 40 ˚C [7]. At this temperature and above a loss peak was observed at low frequencies that merged into a power law response at higher frequencies and eventually into a high frequency loss peak at ∼3 10 5 Hz. A dc conductivity masking the low frequency side of the alpha peak was observed at T≥70 ˚C, figure 1. An Arrhenius plot of the low frequency peak show the approach to zero frequency typical of the alpha response of a glass transition, figure 2. The power law response is less clear-cut as it is partially obscured by the two...

show abstract

Section: Space Charge Measurementssupporting

confidence: 75%

Charge injection, electroluminescence, and ageing of an epoxy resin in high divergent fields

Griseri

Fukunaga²,

Laurent³

et al. 2000

Eighth International Conference on Dielectric Materials, Measurements and Applications

View full text Add to dashboard Cite

show abstract

“…the thermal tecfi'ques are excellent for the investigation of thin films and near surface regions. Recently, several comparisons between the acoustic and thermal techruques have been reported by DeReggi et al[122] (thermal pulse and laser induced pressure pulse LIPP), Alquie et al[123] (thermal wave and LIPP), Yang et al[124] (thermal wave and LIPP on electron beam poled…”

mentioning

confidence: 99%

Pyroelectric polymer electrets

Bauer

Lang

1996

IEEE Trans. Dielect. Electr. Insul.

View full text Add to dashboard Cite

Pyroelectricity is the electrical response of a material to a change in temperature. It exists in polymers which contain spontaneous or frozen polarization resulting from oriented dipoles. This review describes the physical basis for the existence of the pyroelectric effect and discusses its behavior in a number of amorphous, semicrystalline, crystalline and liquid crystalline polymers. Some of the techniques for measurement of the pyroelectric effect are presented and its use in pyroelectric relaxation spectroscopy and thermal analysis is described. The spatial distribution of polarization and space charge through the thickness of polymer films can be determined by several thermal pyroelectric techniques. Recent developments in the integration of pyroelectric polymer infrared detectors with solid-state silicon devices are described. One of the most important recent applications of polymers is in photopyroelectric spectroscopy which can be used for the determination of a number of thermal and optical properties of materials. Finally, some miscellaneous applications in physics, chemistry and biology are presented.Polar liquid crystals (LC) seem to,be very interesting materials for pyroelectric applications, due to the strong orientation of

show abstract

“…36 These acquire charge or become polarized, generally inhomogeneously, under high applied fields ͑Ͼ10 V/m͒, high temperature ͑Ͼ60°C͒, or both. 32,37 Even polymers with high glass transition temperatures such as polyamides 38 and polyimides 39 may acquire charge ͑or become polarized͒ when voltage biased.…”

Section: Introductionmentioning

confidence: 99%

Electric-field profile and thermal properties in substrate-supported dielectric films

2000

View full text Add to dashboard Cite

The transient pyroelectric response of a dielectric film on a substrate is used to determine both the electricfield profile across the film and its thermal properties. The response is a convolution of the field and temperature profile. A closed-form expression for the transient temperature profile is obtained for a generic model in terms of thermal parameters. This expression allows analysis of the pyroelectric response using an iterative procedure consisting of deconvolution and variation of thermal parameters. Tikhonov regularization is used in the deconvolution with a Honerkamp-Weese self-consistent regularization parameter. Simulations show that, at least in the cases tested, the electric-field profile, the thermal diffusivity and conductivity ͑and thus the heat capacity, which is their ratio͒, and the thermal resistance of the dielectric/substrate interface can be determined. Experiments on polyimide films adhered to substrates unambiguously reveal bound negative charge within a small depth of the free surface of virgin samples and also weaker, broader charge distributions injected from the substrate in samples under an applied voltage. The analysis resolves both sharp and broad features and gives thermal properties characteristic of the near-surface region, suggesting that the heat capacity may be significantly higher in this region than in the bulk.

show abstract

Determination of the polarization-depth distribution in poled ferroelectric ceramics using thermal and pressure pulse techniques

Cited by 31 publications

References 11 publications

Charge injection, electroluminescence, and ageing of an epoxy resin in high divergent fields

Charge injection, electroluminescence, and ageing of an epoxy resin in high divergent fields

Pyroelectric polymer electrets

Electric-field profile and thermal properties in substrate-supported dielectric films

Contact Info

Product

Resources

About