AVS 50th International Symposium
    Magnetic Interfaces and Nanostructures Wednesday Sessions
       Session MI-WeP

Paper MI-WeP16
Extraordinary Hall Effect in Mn Ion-implanted p@super +@GaAs:C*

Wednesday, November 5, 2003, 11:00 am, Room Hall A-C

Session: Poster Session
Presenter: J.D. Lim, Seoul National University, Korea
Authors: J.D. Lim, Seoul National University, Korea
S.B. Shim, Seoul National University, Korea
K.S. Suh, Seoul National University, Korea
Y.D. Park, Seoul National University, Korea
C.R. Abernathy, University of Florida
S.J. Pearton, University of Florida
R.G. Wilson, Consultant
Correspondent: Click to Email
Gas source molecular beam epitaxy (GSMBE) prepared p@super +@GaAs:C (p = 3 x 10@super 20@cm@super -3@) on SI GaAs substrate was ion-implanted with Mn at 250 keV (at 350° C) with dose ranging from 1 - 5 x 10@super 16@ cm@super -2@. AC-magnetotransport measurements were conducted in Van der Pauw geometry using indium soldered contacts on as-implanted samples (I@sub ac@ = 100@mu@A @@ 17.1 Hz). Resistivity as function of temperature (@rho@ vs. T) for various applied fields showed anomalies consistent with magnetic properties. For various applied fields (up to 9 Tesla) for the temperature range considered (5 K - 400 K), the magnetoresistance (MR) was found to be positive, as oppose to nanometer-sized ferromagnetic clusters embedded in semiconductor matrix systems, which generally show a cross-over in sign of MR.@footnote 1@ Hall Effect measurement show a positive response consistent with overall p-character of the implanted samples. Sheet resistance increased with dose due to the expected implantation damage, and sheet carrier concentration as measured at 300 K increased with dose. Determination of the exact carrier concentration was made difficult with the onset of extraordinary Hall Effect (EHE) below 280 K (where @rho@@sub H@=R@sub o@B + R@sub S@H), again consistent with magnetic properties. For specific temperature range, the dominant EHE mechanism was found to be skew scattering (R@sub s@ ~ c@rho@). An apparent mobility enhancement was not observed as reported in inhomogeneous systems.@footnote 2@ Along with detailed magnetotransport measurements, effects of temperature of sample during implantation process and post-implantation anneal processes will be discussed. @FootnoteText@@footnote *@ partially supported by Samsung Electronics Endowment and KOSEF through CSCMR.@footnote 1@ H. Akinaga et al., Appl. Phys. Lett. 72, 3368 (1998); D.R. Schmidt et al., Phys. Rev. Lett. 82, 823 (1999).@footnote 2@ Sh.U. Yuldashev et al., J. Appl. Phys. 90, 3004 (2001).