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Usually, the trapping phenomenon in insulating materials is studied by injecting charges using a Scanning Electron Microscope. In this work, we use the dielectric spectroscopy technique for showing a correlation between the dielectric properties and the trapping-charging ability of insulating materials. The evolution of the complex permittivity (real and imaginary parts) as a function of frequency and temperature reveals different types of relaxation according to the trapping ability of the material. We found that the space charge relaxation at low frequencies affects the real part of the complex permittivity ε′ and the dissipation factor Tan(δ). We prove that the evolution of the imaginary part of the complex permittivity against temperature ε″=f(T) reflects the phenomenon of charge trapping and detrapping as well as trapped charge evolution Qp(T). We also use the electric modulus formalism to better identify the space charge relaxation. The investigation of trapping or conductive nature of insulating materials was mainly made by studying the activation energy and conductivity. The conduction and trapping parameters are determined using the Correlated Barrier Hopping (CBH) model in order to confirm the relation between electrical properties and charge trapping ability.

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Dielectric breakdown constitute an important limitation in the use of insulating materials since it causes its damage. This catastrophic phenomenon (Figure 1) is obviously an important failure in the levels of equipment requiring some insulation safety or ensuring their proper functioning. This causes some technological problems associated with the manufacture and use of insulating materials in several industrial sectors like in microelectronics, high voltage electric energy transport and spacecraft. The choice of insulating material for those applications is related to the corresponding breakdown voltage value which limits their use. To improve the resistance to dielectric breakdown, it is imperative to understand and control the cause of this damage process reducing the reliability of some instrumentation. It is well known that breakdown is correlated with the presence of space charge within the insulators. Indeed, breakdown is related to a fast relaxation (detrapping) of trapped charge. Commonly, this space charge can be determined by the SEMME method (Scanning Electron Microscope Mirror Effect) which quantifies the final trapped charge amount. The purpose of this work is to develop a technique using a specific arrangement in the SEM chamber (Figure 2) in order to characterize the trapped charge dynamic by ICM (Induced Current Method). This technique allows enhancing the understanding of trapping phenomenon, spreading and stability of trapped charges The experiments were carried out in a FESEM (Field Emission Scanning Electron Microscope) Carl Zeiss SUPRA 55 VP using a specific configuration in the SEM sample holder (Figure 3). It permits to measure separately and simultaneously the influence current and the conduction current and tracing back to the trapped charge temporal evolution during (charging) and after (charge decay) electrons irradiation (Figure 4). Thereafter, the used technique of two injections separated by a pause time was a powerful method for monitoring and understanding the dynamics of the trapped and released charges in insulating materials. These results open the way for the establishment of a conventional characterization procedure, which will be useful in different contexts of use of insulating materials. The studied materials are α‐alumina and Yttria Stabilized Zirconia (YSZ) polycrystalline ceramics. Since the dielectric and electrical properties of an insulating material are highly dependent on its microstructure, the grain size effect and MgO doping effect are then studied and discussed. Via the developed technique, the microstructure ‐ dielectric rigidity correlations could be well justified.