Relations between ionic conductivity and magnetization intensity in Na- and K-β″-ferrite with water uptake

The relations between ionic conductivity and magnetization intensity in Na- and K-β″-ferrites with water uptake were studied. Upon hydration, Na-β″-ferrite shows decrement of the ionic conductivity (ranging from 7.87×10^-2 to 7.13×10^-4 S/m at 548 K) and enhancement of the magnetization (maximum 13.6 Am²/kg by hydration for 25 h). On the contrary, K-β″-ferrite shows a relatively small variation of ionic conductivity and magnetization intensity upon hydration in comparison with those of Na-β″-ferrite. This different behavior of magnetization and ionic conductivity between Na- and K-β″-ferrite will be associated with the amount of water uptake, namely the difference in reactivity between Na and K in the crystals.