Pulsed laser deposition of iron oxide and ferrite films

Abstract

Iron oxide and ferrite films were prepared by pulsed ruby laser evaporation from the respective bulk materials on alumina substrates. The variation in the film properties as a function of the substrate temperature and oxygen partial pressure during deposition was studied. Conversion electron Mössbauser spectroscopic analysis showed that the stoichiometry and microstructure of such films depend on these deposition conditions, especially the oxygen partial pressure in the system. Typically it was observed that when laser deposition is performed by vaporizing α-Fe2O3 in the oxygen partial pressure of 10−4 Torr, Fe3O4 thin films were formed while deposition at a background pressure of 10−6 Torr led to formation of FeO films. Similar experiments were also performed on zinc ferrite and it was observed that the nanosecond pulsed evaporation process transports the stoichiometry of metal constituents from the bulk to the film with a small degree of zinc enrichment. In addition to Mössbauer spectroscopy, other techniques such as scanning electron microscopy and x-ray diffraction were also used to characterize the laser-deposited films.