  Oxygen-vacancies-related dielectric relaxation and scaling behaviors of
Bi0.9La0.1Fe0.98Mg0.02O3 (BLFM) thin film have been investigated by
temperature-dependent impedance spectroscopy from 40 oC up to 200 oC. We found
that hopping electrons and single-charged oxygen vacancies (VO.) coexist in the
BLFM thin film and make contribution to dielectric response of grain and grain
boundary respectively. The activation energy for VO. is shown to be 0.94 eV in
the whole temperature range investigated, whereas the distinct activation
energies for electrons are 0.136 eV below 110oC and 0.239 eV above 110oC in
association with hopping along the Fe2+- VO.-Fe3+ chain and hopping between
Fe2+-Fe3+, respectively, indicating different hopping processes for electrons.
Moreover, it has been found that hopping electrons is in form of long rang
movement, while localized and long range movement of oxygen vacancies coexist
in BLFM film. The Cole-Cole plots in modulus formalism show a poly-dispersive
nature of relaxation for oxygen vacancies and a unique relaxation time for
hopping electrons. The scaling behavior of modulus spectra further suggests
that the distribution of relaxation times for oxygen vacancies is temperature
independent.
