AVS 50th International Symposium
    Surface Science Friday Sessions
       Session SS2-FrM

Paper SS2-FrM3
Electronic Structure at the Fe@sub 3@O@sub 4@/NiO Interface@footnote 1@

Friday, November 7, 2003, 9:00 am, Room 328

Session: Oxide Surfaces and Interfaces
Presenter: H.Q. Wang, Yale University
Authors: H.Q. Wang, Yale University
W. Gao, Yale University
E.I. Altman, Yale University
V.E. Henrich, Yale University
Correspondent: Click to Email
The interfacial electronic structure between the metallic ferrimagnet Fe@sub 3@O@sub 4@ and the insulating antiferromagnet NiO has been investigated in the heteroepitaxial system Fe@sub 3@O@sub 4@ (100)/NiO (100) by growing from submonolayer to multilayer films of NiO (100) on single-crystal Fe@sub 3@O@sub 4@ (100) substrates. The lattice mismatch in this system is only 0.55 %, and excellent superlattice structures have been grown previously by other groups. The presence of tetrahedral Fe@super 3+@ ions lying above the plane of O anions and octahedral Fe cations on Fe@sub 3@O@sub 4@ (100) results in unusually short Fe-Ni cation-cation distances in the stoichiometric interface structure with rocksalt NiO. The Fe@sub 3@O@sub 4@ surface prior to growth is characterized by LEED, RHEED and STM; both the (1x1) and (@sr@2x@sr@2)R45° surface reconstructions have been studied. The NiO growth morphology is measured with STM. The electronic structure is monitored versus overlayer thickness by using UPS, XPS, Auger and EELS spectroscopies, which were chosen because they sample several monolayers (ML) into the substrate/overlayer structure. The overlayer thickness dependence of spectral features is then used to separate interfacial states from those of the substrate and the overlayer film. The evolution of the density-of-states in the O 2p-Fe 3d-Ni 3d band has been observed during the first few ML of NiO deposition. Changes occur across the entire band (from E@sub F@ to about 12 eV below E@sub F@). For NiO layers thicker than about 3 ML, the overlayer electronic structure is essentially that of bulk NiO. @FootnoteText@ @footnote 1@This research was partially supported by U.S. Department of Energy Grant DE-FG02-00ER45844; and NSF equipment grant DMR-0075824.