Electrical conductivity and capacitance spectra of Bi_1.37Sm_0.13Zn_0.92Nb_1.50O_6.92 pyrochlore ceramic in the range of 0–3 GHz

Abstract

In this work, the electrical properties of samarium-doped bismuth niobium zinc oxide ( Sm -doped BZN ) pyrochlore ceramics are investigated by means of temperature dependent electrical conductivity and capacitance spectroscopy in the frequency range of 0–3 GHz. It was observed that the novel dielectric Sm - BZN ceramic exhibits a temperature and electric field dependent dielectric breakdown. When measured at 300 K, the breakdown electric field is 1.12 kV/cm and when heated the breakdown temperature is ~ 420 K. The pyrochlore is thermally active above 440 K with conductivity activation energy of 1.37 eV. In addition, the room temperature capacitance spectra reflected a resonance–antiresonance switching property at 53 MHz when subjected to an AC signal of low power of 5 dBm. Furthermore, when the Sm - BZN ceramics are used as microwave cavity and tested in the frequency range of 1.0–3.0 GHz, the cavity behaves as low pass filter with wide tunability up to a frequency of 1.91 GHz. At this frequency it behaves as a band rejection filter that blocks waves of 1.91 GHz and 2.57 GHz frequencies. These properties of the Sm -doped BZN are promising as they indicate the usability of the ceramics in digital electronic circuits as resonant microwave cavities suitable for the production of low pass/rejection band filters.

Tungsten doped Bi1.5Zn0.92Nb1.5O6.92 ceramics designed as radio/microwave band pass/reject filters

“…In addition, the conductance spectra displayed peaks at 0.19 and 0.44 GHz, and at 1.33 and at 1.59 GHz, respectively. Similar features of capacitance spectra in the radiowave region were previously observed for Sm doped BZN at 53 MHz 11 . The observed resonance‐antiresonance phenomena in the capacitance spectra that are associated with negative capacitance (NC) effect indicates the ability of using the W‐BZN ceramics as radio/microwave cavities.…”

“…The observed resonance‐antiresonance phenomena in the capacitance spectra that are associated with negative capacitance (NC) effect indicates the ability of using the W‐BZN ceramics as radio/microwave cavities. The NC effect was not observed for Sm‐BZN ceramics 11 . This feature indicates the achievement of better properties of the BZN via W doping over Sm doping.…”

“…The NC effect was not observed for Sm-BZN ceramics. 11 This feature indicates the achievement of better properties of the BZN via W doping over Sm doping. The NC effect which was observed in W-BZN samples is beneficial for noise reduction and parasitic capacitance cancellation.…”

“…The lower the impedance, the better the signalto-noise ratio, the lower the coupling loses, the greater the signal response. 17,18 Better screening of the effect of these two observed minima can be seen from the calculated S 11 (Z L = 1 + S 11 1− S 11 Z o ) parameter spectra. This parameter connects a relation between the impedance of the signal source (Z o ) and that of the device (Z L ).…”

“…Similar features of capacitance spectra in the radiowave region were previously observed for Sm doped BZN at 53 MHz. 11 The observed resonance-antiresonance phenomena in the capacitance spectra that are associated with negative capacitance (NC) effect indicates the ability of using the W-BZN ceramics as radio/ microwave cavities. The NC effect was not observed for Sm-BZN ceramics.…”