Electron energy loss spectroscopy studies of the amorphous to crystalline transition in FeF3

Electron beam-induced crystallization studies in amorphous FeF3 films using electron energy loss spectroscopy (EELS) are discussed in this letter. Time-resolved EELS studies show that the coordination polyhedra in amorphous FeF3 (a-FeF3) are randomly arranged FeF6 octahedra. They arrange themselves to give long range order during crystallization to FeF2 and FeF3 under the electron beam. Changes in the d-band occupancy by one electron as well as the sensitivity of the ratio of the Fe L3 and L2 edges to the electronic configuration of the iron ion are clearly seen during the crystallization process.