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

Paper MI-TuM5
Determination of the Influence of the Interfacial Formation and the Semiconductor Doping Profiles on the Spin Injection from Fe@sub x@Co@sub 1-x@ Contacts into Ga@sub x@Al@sub 1-x@As

Tuesday, November 16, 2004, 9:40 am, Room 304A

Session: Spintronics
Presenter: C. Adelmann, University of Minnesota
Authors: C. Adelmann, University of Minnesota
X.Y. Dong, University of Minnesota
B.D. Schultz, University of Minnesota
C.J. Palmstrøm, University of Minnesota
J. Strand, University of Minnesota
X. Lou, University of Minnesota
P.A. Crowell, University of Minnesota
S. Park, Los Alamos National Laboratory
M.R. Fitzsimmons, Los Alamos National Laboratory
Correspondent: Click to Email
Spin injection from ferromagnetic contacts into semiconductor structures is a crucial part in spintronic devices operating at room temperature. Recently, it has been shown that spin injection is possible from Fe into GaAs by tunneling through a reverse-biased Schottky contact into an light emitting diode@footnote 1@. The dependence of spin injection on the inter-face doping level and drift layer doping was studied. Efficient spin injection was only obtained in a narrow interface doping window between 3E18 and 5E18 cm@super -3@. The optimum drift layer doping was found to be about 1E16 cm@super -3@. The spin detection efficiency was also found to depend on the p-layer. The carrier transport as a function of doping level will be discussed. The effect of growth temperature and annealing on the spin injection was also investigated. Low temperature annealing was found to increase the electroluminescence polarization. However, at high annealing temperatures, no spin injection was observed suggesting reactions between GaAs and the metal contact. The observed changes in electroluminescence polarization were found to correlate with the changes in the interfacial magnetic properties for Fe@sub 0.5@Co@sub 0.5@/GaAs heterostructures determined from polarized neutron reflectivity. Optimized devices were found to lead to >10% spin injection at room temperature. This work was supported by the DARPA SPINS program, ONR, and the University of Minnesota NSF-MRSEC program. @FootnoteText@ @footnote 1@ A.T. Hanbicki et al., Appl. Phys. Lett. 80, 1240 (2002).