Dresden 2003 – wissenschaftliches Programm
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MA: Magnetismus
MA 7: Spin-Elektronik
MA 7.15: Vortrag
Montag, 24. März 2003, 18:45–19:00, HSZ/401
Magnetic properties of Mn and Cr implanted GaN layers — •V.A. Guzenko, N. Thillosen, Th. Schäpers, N. Kaluza, and A. Dahmen — Institut für Schichten und Grenzflächen (ISG1), Forschungszentrum Jülich GmbH, 52425 Jülich
By implantation of magnetic atoms, e.g. Mn or Cr, in GaN, ferromagnetic semiconducting films can be prepared. Due to theoretical predictions the Curie temperature Tc of such materials can be even higher than room temperature. It was reported that the magnetic properties of such layers depend strongly on the annealing conditions subsequent to the implantation process.
As substrates nominally undoped GaN layers grown by MOCVD on the sapphire substrate were used. The Mn and Cr atoms were implanted to the semiconductor crystal at an energy of 200 keV. Room temperature SQUID magnetometer measurements of samples, annealed at temperatures between 700 and 1150 ∘C, revealed the presence of hysteresis. The effect of p-doping on the ferromagnetic coupling was investigated by additionally implanting Mg atoms. It was found that the Mg p-doping increases the saturation magnetization of the ferromagnetic layers.