Tunability of ac conductivity in manganese doped cobalt ferrite nanoparticles

This paper reports on the experimental findings of ac conductivity as determined from the measurement of conductance by using the Waynekerr 6500B impedance analyzer for the stoichiometric and non-stoichiometric manganese doped cobalt ferrite nanoparticles. In the dispersion of ac conductivity over the frequency band 100 Hz–1 MHz, two distinct conductive bands 100 Hz–1 kHz and 1 kHz–1 MHz for stoichiometric compositions, and 100 Hz–3 kHz and 3 kHz–1 MHz for non-stoichiometric compositions are observed. On the other hand, well-resolved peaks are observed in the dispersion of ac conductivity over the frequency band 1–120 MHz that corresponds to the hopping resonance for both the compositions. The ac conductivity is found to be tunable by the Mn content and selectable by the frequency between cutoff frequencies for both the compositions. A comparatively higher magnitude of ac conductivity is observed for the representative sample of non-stoichiometric composition and a lower magnitude for the stoichiometric compositions. The presence of tunability of ac conductivity in the studied samples is, therefore, a concern on which basis, the Joule’s heat and Joule’s heat per unit time have been determined for the studied samples by using the usual formula and also found to be tunable by the manganese content. This tunability of the generated Joule’s heat may make these possible to use in the temperature switching/sensing, and/or thermoelectric/thermomagnetic devices.