Abstract
In this paper, the influence of pressure on the impedance and resistance of SnO2 nanopowder has been investigated. A transducer is fabricated for the direct measurement of impedance-pressure relationships on nanopowder. At initial conditions, the diameter and the height of nanopowder samples placed in the transducer are 10 mm and 3 mm, respectively. Under pressure of up to 8.15kN/m(2), the DC resistance and the impedance decrease on average up to 22% in the frequency range of 100 Hz to 200 kHz. This decrease in resistance and impedance may be regarded to the densification of samples and decrease in porosity under pressure. These impedance-pressure and resistance-pressure relationships are quasi-linear and it is also observed that the DC resistance increases with time and gets saturated within 5 minutes. This phenomenon is regarded to the effect of displacement currents of bound charges. The resistance-pressure relationship is simulated and the dependence of impedance phase (theta) on the frequency and pressure is also investigated.