Epitaxially grown iron oxide films have been studied microscopically by conversion electron M~ssbauer spectroscopy. Specially designed proportional counters cover a temperature range between 1.75K and 1100K. A 5Å-thick layer containing 57Fe was grown at an arbitrary depth of a 56 Fe3O4 film, even- at the topmost or at the interface with a substrate crystal, to find local properties nondestructively. Temperature dependence of the hyperfine parameters of Bi 3 Fe5O12 films were analyzed to find structural and magnetic effects of Bi3+ in comparison with usual garnets. The Morin transition of α-Fe2O3 was found to strongly depend upon the orientation of films and post-annealing.