AVS 47th International Symposium
    Magnetic Interfaces and Nanostructures Wednesday Sessions
       Session MI+EL-WeM

Paper MI+EL-WeM8
Growth and Magnetic Properties of Epitaxial Fe-N Films@footnote 1@

Wednesday, October 4, 2000, 10:40 am, Room 206

Session: Magnetic Semiconductors and Hybrid Structures I
Presenter: F. Liu, University of Alabama
Authors: F. Liu, University of Alabama
S.-C. Byeon, University of Alabama
C. Alexander, University of Alabama
G.J. Mankey, University of Alabama
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Reported values of magnetic moments in epitaxial Fe@sub 16@N@sub 2@ films vary from 2.3 to 3.5 Bohr magnetons per atom.@footnote 2@ These discrepancies arise from the fact that the films are multiphase mixtures which decompose upon heating.@footnote 3@ To study this problem, 40 nm thick Fe-N films were produced using reactive sputtering in an ultra clean sputtering system with in situ RHEED. First, an S-terminated GaAs surface is prepared by wet chemical etching. After annealing at 450 C, a 3 nm thick Fe seed layer is deposited to promote epitaxial growth of a 20 nm thick Ag(100) buffer layer. The Fe-N film is then grown on this Ag(100) buffer. The sputtering power, Ar + N@sub 2@ pressure, and the substrate temperature were varied systematically to produce the optimal RHEED pattern. The films were capped with a 5 nm thick Ru layer for ex situ structural and magnetic analysis. XRD is used to identify the degree of N-site ordering and the unit cell volume. XPS depth profiling is used to determine the chemical composition of the Fe-N film. The structural and chemical measurements are correlated with ferromagnetic resonance and vibrating sample magnetometry measurements of the saturation magnetic moment. These results are used to clarify the origin of the "giant magnetic moment" in the ordered Fe@sub 16@N@sub 2@ phase. @FootnoteText@ @footnote 1@Funded by ARO #DAAH 04-96-1-0316 and NSF #DMR-9809423. @footnote 2@G.W. Fernando et al., Phys. Rev. B 61, 375(2000). @footnote 3@ Migaku Takahasi and H. Shoji, J. Magn. Magn. Mater. 208, 145(2000).