Abstract:
Comparative studies of the experimental and calculated, based on a mathematical model, dielectric response of porous potassium sodium niobate (KNN) ceramics with a pore content of 10, 25 and 40 volume percent were carried out. Based on mathematical modeling, it is shown that in KNN samples without pores, the contribution to the dielectric response of relaxation conductivity is present only in the monoclinic phase (temperature range 200 – 400$^\circ$C). The presence of pores in KNN samples leads to the appearance of additional contributions of conduction processes to the dielectric response. In the experiments, this manifests itself as the appearance of additional (in comparison with a similar dependence for a sample without pores) linear segments on the dependence of the real part of the complex conductivity on the inverse temperature in Arrhenius coordinates. This indicates a set of activation energies and, as a consequence, the presence of various conductivity mechanisms in porous samples.
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