We report on a theoretical and experimental study of the growth, electronic structure, and thermal stability of ultrathin films of nonmagnetic iron nitride. The films are grown by evaporation of Fe, in a flux of atomic N produced by a plasma source, onto a Cu(001) surface kept at 300 K and characterized by x-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and x-ray diffraction. The compound formed is identified as γ″ -FeN (001) growing epitaxially on the substrate. Its electronic structure and thermal stability has been studied and compared with first-principles calculations. This nitride film transforms to magnetic γ′ -Fe4 N phase by annealing above 650 K, opening new perspectives for applications of these films in functional magnetic nanostructures. © 2008 The American Physical Society.

This work was supported by the Spanish CICyT under Grants No. FIS 2007-61114, No. MAT2004-05865, No. NAN2004-08881-C02-01, and CONSOLIDER on Molecular Nanoscience, the Comunidad de Madrid under Grant No. S-0505/MAT-0194, and the EU under the PF6 “Structuring the European Research Area” program Contract No. RII3- CT-2004-506008.

6 págs.; 7 figs. ; PACS number s : 73.20. r, 71.20. b, 71.15.Mb, 68.37.Ef

Peer Reviewed