AVS 51st International Symposium
    Magnetic Interfaces and Nanostructures Tuesday Sessions
       Session MI-TuM

Paper MI-TuM3
Characterization of Thin Film MnGa/GaAs(001) Heterostructures

Tuesday, November 16, 2004, 9:00 am, Room 304A

Session: Spintronics
Presenter: J.L. Hilton, University of Minnesota
Authors: J.L. Hilton, University of Minnesota
B.D. Schultz, University of Minnesota
S. McKernan, University of Minnesota
C.J. Palmstrøm, University of Minnesota
Correspondent: Click to Email
MnGa thin films are desirable for use as ferromagnetic contacts in spintronic devices because they can be grown epitaxially on GaAs with perpendicular magnetization@footnote 1@. The interface between the ferromagnetic contact and the semiconductor has a significant influence on the spin injection efficiency of spintronic devices. It has been shown previously that elemental Mn is not stable on GaAs and that it reacts to form an interfacial region composed of Mn@sub 2@As and MnGa@footnote 2@, suggesting that MnGa may be stable in contact with GaAs. However, bulk material studies suggest that Mn@sub 2@As and elemental Ga are the two stable phases in contact with GaAs@footnote 3@. To address this discrepancy, a number of MnGa/GaAs heterostructures were grown by MBE and subsequently annealed either in-situ or ex-situ for different times and temperatures. X-ray diffraction of MnGa/GaAs samples following growth shows peaks corresponding to both MnGa(001) planes and the GaAs substrate. Following post-growth anneals at 400°C for 1 hr, peaks corresponding to (001) planes of the Mn@sub 2@As-like crystal structure are observed. Rutherford backscattering spectrometry shows only minor compositional changes upon annealing, indicating that any reactions are confined to the interfacial region. These results will be combined with results from in-situ RHEED, LEED, STM, and XPS, and ex-situ RBS channeling and TEM to characterize the growth and interfacial properties of epitaxial MnGa/GaAs heterostructures. Supported by ONR, DARPA, NSF, and AFOSR. @FootnoteText@ @footnote 1@M. Tanaka et al., Appl. Phys. Lett. 62, 1565 (1993).@footnote 2@J. L. Hilton et al., Appl. Phys. Lett. 84, 3145 (2004).@footnote 3@P. Kordos et al., Solid State Electron 18, 223 (1975).