Electrical measurements in a dynamic experiment

The location of light emission sources in shocked polytetrafluoroethylene is analyzed. It is found that the state of the plate-sample interface has a great effect on the emission profile. Time-correlated pressure and emission profiles and electrical resistance profiles of polytetrafluoroethylene sample were recorded, which allowed the times of the occurrence and the duration of the emission signals to be determined. The emission pulse profile was calculated under some simplifying assumptions on the emittance of the shock-compressed part of the sample. It is shown that, ahead of the shock front, a zone arises in which the resistance of polytetrafluoroethylene decreases by nine to ten orders of magnitude, depending on the state of the interface. It is suggested that a photoconductivity wave induced by the light occurs ahead of the shock front.

Section: Time Correlation Between Emission Signals and The Occurrencementioning

confidence: 99%

Light emission from polytetrafluoroethylene in a shock of intensity 51 GPa

Bordzilovskii

Karakhanov

2007

“…It is based on using an electric field generated in a material due to the piezoeffect or shock depolarization produced by a shock wave (SW). The need for the development of this method is motivated by the fact that the field strength in shock-compressed polar dielectrics can reach 10 7 -10 8 V/m [2], which complicates measurements of their SIEC by known electricalcontact methods with the voltage applied to the sample from an external source [3]: it is almost impossible to identify the examined effect against a background of the proper field.…”

Section: Introductionmentioning

confidence: 99%

Shock-induced electrical conductivity in some ferroelectrics

Bragunets

Simakov

Borisenok

et al. 2010

“…There has been an attempt to measure SIEC in piezoceramics using the voltmeter-ammeter method and the oscillating circuit method [6]. Generally, however, measurements can be performed on unpolarized material samples or 1 Institute of Experimental Physics Russian Federal Nuclear Center, Sarov 607190; root@gdd.vniief.ru.…”

mentioning

confidence: 99%

“…Results of measurements of electrical conductivity in single-crystal quartz are reported.An analysis of the literature [1] shows that the overwhelming majority of experimental data on the shockinduced electrical conductivity of materials were obtained by electrocontact methods of measuring electrical resistance. All of them are based on the application of an electrical voltage to the material sample studied or on the passage of an electric current from an external source through the sample [1].…”

mentioning

confidence: 99%

“…All of them are based on the application of an electrical voltage to the material sample studied or on the passage of an electric current from an external source through the sample [1]. These methods, however, are unsuitable for measuring shock-induced electrical conductivity (SIEC) in piezoelectrics and ferroelectrics because shock-wave (SW) action generates an electric field of strength up to 10 7 -10 8 V/m [2] in these materials due to the piezoeffect or shock depolarization, and the effect in question can hardly be identified against the background of the generated fields.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Measuring shock-induced electrical conductivity in piezoelectrics and ferroelectrics. Single-crystal quartz

Borisenok

Kruchinin

Bragunets

et al. 2007

A method is proposed to measure shock-induced electrical conductivity in electrically active dielectrics -piezoelectrics and ferroelectrics. Results of measurements of electrical conductivity in single-crystal quartz are reported.An analysis of the literature [1] shows that the overwhelming majority of experimental data on the shockinduced electrical conductivity of materials were obtained by electrocontact methods of measuring electrical resistance. All of them are based on the application of an electrical voltage to the material sample studied or on the passage of an electric current from an external source through the sample [1]. These methods, however, are unsuitable for measuring shock-induced electrical conductivity (SIEC) in piezoelectrics and ferroelectrics because shock-wave (SW) action generates an electric field of strength up to 10 7 -10 8 V/m [2] in these materials due to the piezoeffect or shock depolarization, and the effect in question can hardly be identified against the background of the generated fields.SIEC is an important characteristic in the use of piezoelectrics and ferroelectrics as a working medium of dynamic pressure transducers [2] and explosive piezogenerators [3]. However, because of the lack of experimental data on SIEC, this quantity was not taken into account quantitatively in phenomenological and computational models for the electrical response of the abovementioned devices to SW action [2,4,5]. There has been an attempt to measure SIEC in piezoceramics using the voltmeter-ammeter method and the oscillating circuit method [6]. Generally, however, measurements can be performed on unpolarized material samples or the time when depolarization processes in a material have been completed. Therefore, they have a limited range region of application.In the present study, we propose a method for measuring SIEC in piezoelectrics and ferroelectrics which is based on the use of the electric field generated in the material under SW action. A similar approach was employed in [7] to develop a procedure for measuring radiation-induced electrical conductivity in pyroelectrics. SIEC MEASUREMENT METHODLet us derive a differential equation that describes the electrical response of a piezoelectric or ferroelectric sample to SW action taking into account shock-induced electrical conductivity. A schematic representation of the sample is given in Fig. 1.The sample in the shape of a rectangular parallelepiped with dimensions x 0 × y 0 × z 0 is placed in a dielectric medium. Thin metal electrodes are applied on its faces parallel to the plane Y Z. A load resistance R load is switched between the electrodes. A plane SW prorogates at a velocity D along the Z axis.The SW front divides the sample into a compressed and an uncompressed zones. Leakage of the generated electric charge can occur on the face of the sample parallel to the coordinate plane XY (the corresponding surface electrical conductivity is σ 1 ), on the faces par-96 0010-5082/07/4301-0096