It can be seen from the figures that the transition at this temperature is slowly vanishing with increasing La dopent conentration. This is expected because by replacing Bi with La perhaps the oxygen ion vacancies might have decreased thereby decreasing the concentration of Fe2+ considerably. The replacement of some volatile Bi3+ with non-volatile La3+ might have prevented the oxygen ion vacancies stabilizing the Fe3+/Fe2+ couple–oxygen vacancy interaction [24], [25] and [26].