Current Noise in Sodium Beta Alumina Ceramic.
UTAH UNIV SALT LAKE CITY DEPT OF PHYSICS
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Experimental bulk current noise spectra for NaBeta alumina ceramics are observed over the frequency range f.003 Hz to 10,000 Hz and with low contact noise, amalgam electrodes. The noise is proportional to the square of the dc current and varies as 1f times f to the 12 power, suggesting bulk conductivity fluctuations arising from diffusion of the conducting ions. The results indicate that individual grains in the ceramic are not stochastically independent and that only a small fraction of the conducting ions present participate in the diffusion process. The number of such ions present participate in the diffusion noise process. The number of such ions is thermally activated with an activation energy of 0.75 eV. Chemical and electrochemical contact noise indicates a reaction at the ceramic-amalgam interface characterized by a reaction rate of 630sec, even for low-noise contacts.
- Ceramics, Refractories and Glass
- Electricity and Magnetism