Conductivity studies were also made on samples of the same composition
and density. We observed that aluminium- and magnesium doped
samples have better conductivity than the undoped counterpart.
The conductivity values are in the expected order compared with literature
data and confirmed by using the Nernst–Einstein equation. The
role of iron on the conduction mechanism is unclear, but it shows a
positive influence on the conductivity. This behaviour is in agreement
with conductivity measurement results in the literature, where it has
been found that doping with aluminium and magnesium leads to an
increased ionic conductivity.