Comparison of a stoichiometric analysis of Fe_3-deltaO_4 layers by magneto-optical Kerr spectroscopy with Moessbauer results

摘要

The stoichiometry of a series of 300 A thick Fe_3-deltaO_4 layers grown by means of molecular beam epitaxy on MgO(100) has been investigated both by magneto-optical Kerr spectroscopy and by Moessbauer spectroscopy. The layer consisted of a 200 A thick Fe_3-deltaO_4 layer grown with the ~57Fe isotope, sandwiched between two 50 A thick layers grown with natural Fe. It was found that delta varied between 0 and 0.33. From the fits of the polar Kerr spectra of the Fe_3-deltaO_4 layers measured betwee 1.4 and 4.0 eV we find, within experimental accurayc, a stoichiometry that is identical to that determiend by Moessbauer spectroscopy. This confirms that the magneto-optical Kerr spectra can also be used to determine the stoichiometry of thin Fe_3-deltaO_4 films.