Dielectric behavior of red HgI2 under direct bias

Abstract

The dielectric constant and loss were measured at several frequencies and temperatures for red mercuric iodide. The equivalent circuits for the sample, before and after a direct bias has been applied for a long time, are discussed. Complex impedance and loss tangent plots versus frequency and temperature show a contact barrier formation after long time polarization. Results are discussed in terms of gamma radiation detector performance.

Mechanical and electrical behaviour of “Magnex DC” conductive polymer composite

“…At low strain rates, the gas bubbles will have a good chance of emerging easily from these cavities and leave the structure, which is highly defected, with low values of yield stress. However, the observed rapid increase of ~y with log E' at low strain rates (or high temperatures) can be understood from the fact that yielding of the composite is dominated by the yield behaviour of steel fibres, which strongly increase with strain rate [17]. At high strain rates, the yielding mechanism is dominated by the yield behaviour of the polymer matrix in the composite, where a linear dependence is observed as in most polymers.…”

Impedance analysis of the AC behaviour of a thin-film device

“…The electrical properties of the surface and interfacial layers of dielectric specimens are often different from those of the bulk of the material. These differences are often attributable to contact effects between the electrodes and the specimen [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. The phenomenon is important both from the view-point of the measurement and interpretation of the electrical and dielectric properties of dielectrics and from the view-point of the application of these materials in engineering practice.…”

“…For thin dielectric and semiconductor specimens, contact effects have a greater influence on the properties of the combination of metallic electrode-dielectric-metallic electrode 0953-8984/97/173609+15$19.50 c 1997 IOP Publishing Ltd than they have for thick specimens, and the difference between measured properties and internal properties becomes correspondingly more significant. These effects have become of practical significance as electrical or microelectronic devices usually incorporate integrated-circuit combinations such as metal-insulator-metal, metal-semiconductor-metal and similar thin-film arrangements [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. In general, these thin-film systems usually involve inhomogeneous parts brought about by structural changes and/or by the creation of surface layers caused by the absorption of atoms, ions or electrons from the surroundings.…”

“…A powerful customary experimental method which has been invoked to investigate the AC behaviour of such electrical-circuit combinations is the use of AC-impedance spectroscopy techniques [10][11][12][13][14][20][21][22][23][24][25]. The results of these AC methods are often analysed and interpreted by adopting a proper equivalent-circuit model as such an approach usually enables one to separate the influence of the electrode and interfacial effects from the inherent bulk properties of the device under investigation.…”

“…In general, one cannot find a universal type of equivalent-circuit model that describes the electrical AC behaviour of all dielectric systems, and even an individual one can only be assumed to be a simplified representation and/or to achieve a specific interpretation of the experimental results. The electrical-circuit models based on the conventional Maxwell-Wagner (MW) two-layer capacitor system [3][4][5][6] or those considering the physical meaning of an electrical or optoelectronic device [10][11][12][13][14][21][22][23][24][25] are sometimes applicable and informative. We have adopted the MW model as well as a specific physical model of the latter type to describe the structure of our device and its overall electrical and dielectric properties as will be discussed later.…”