In this paper, impedance and dielectric properties of nonsuperconducting state of the mercury-based cuprate have been investigated by impedance measurements within the frequency interval of 10 Hz–10 MHz for the first time. The dielectric loss factor [Formula: see text] and ac conductivity [Formula: see text] parameters have also been calculated for non-superconducting state. According to impedance spectroscopy analysis, the equivalent circuit of the mercury cuprate system manifests itself as a semicircle in the Nyquist plot that corresponds to parallel connected resistance–capacitance circuit. The oscillation frequency of the circuit has been determined as approximately 45 kHz which coincides with the low frequency radio waves. Moreover, it has been revealed that the mercury-based cuprate investigated has high dielectric constants and hence it may be utilized in microelectronic industry such as capacitors, memory devices etc., at room temperature. In addition, negative capacitance (NC) effect has been observed for the mercury cuprate regardless of the operating temperatures at nonsuperconducting state. Referring to dispersions in dielectric properties, the main contribution to dielectric response of the system has been suggested as dipolar and interfacial polarization mechanisms.

No abstract

No abstract

In this study, the AC impedance, the complex dielectric function, and the complex electric modulus properties of mercury based copper oxide layered cuprates, which have superconducting properties below the critical transition temperature, have been investigated at room temperature. The HgBa2Ca2Cu3O8+x samples were synthesized by a conventional, solid state reaction preparation method with an identical stoichiometric ratio. The varied oxygen content of the sample was obtained by oxygen annealing. The AC impedance and the related dielectric and electric modulus properties of non-oxygen doped (i. e. as grown) and optimum oxygen doped HgBa2Ca2Cu3O8+x samples, was measured by an impedance analyzer at room temperature within the frequency interval of 10 Hz–10 MHz. AC impedance spectroscopy analyses of the samples suggest Koop's bilayer model for the structure of Hg-based perovskites. Additionally, the optimally oxygen doped process increased grain and grain boundary resistance along with decreasing grain size. Moreover, AC conductivity results have also confirmed the increased resistive behavior of the sample due to oxygen doping. Furthermore, complex dielectric function analyses have determined an oxygen doping induced negative dielectric constant for the mercury cuprates. In this context, optimally oxygen doped mercury cuprate has a promising potential for metamaterial coating applications.

As is known, cuprate superconductors, which have intrinsic Josephson junctions, are used as terahertz sources. In this context, a great number of studies on the intensification of the plasma frequency in terahertz region are devoted to the fabrication of mesa structures in superconductors. It has been previously investigated by some researchers that the resonant state of cuprate superconductors enhances the power of the plasma frequency in terahertz range. As is known, the mercury-based superconductors exhibit three-dimensional Bose–Einstein condensations; hence the resonant state occurs in the sample. From this point of view, mesa structures, which are intrinsically formed in mercury cuprates, have been investigated to enhance the plasma frequency in this work. Also, I have found a physical relation between the lateral size and the Josephson penetration depth of the superconducting sample. Moreover, it has been found that at upper and the lateral size values with microdimension, the superconductors investigated behaves as a bulk in the context of the critical parameters. Furthermore, the method recommended in this study would make crucial contributions to technological applications on mesa structures in order to determine the convenient mesa size that prevents vesting time and energy for the fabrication.