Dresden 2009 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 24: Magnetic Semiconductors
MA 24.10: Vortrag
Mittwoch, 25. März 2009, 17:00–17:15, HSZ 401
Structural and magnetic properties of pulsed laser annealed GaMnAs — •Danilo Bürger1, Mukesh Pandey2, Shengqiang Zhou1, Jörg Grenzer1, Helfried Reuther1, Wolfgang Anwand1, Manfred Helm1, and Heidemarie Schmidt1 — 1Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany) — 2High Pressure Physics Division, Bhabha Atomic Research Centre, 400085 Mumbai (India)
Magnetic semiconductors with high Curie temperatures TC and large coercivity are very promising materials for spintronic applications. An approach to fabricate GaMnAs is the Mn-implantation of GaAs followed by pulsed laser annealing (PLA). We investigated the influence of Mn concentration and PLA conditions, e.g. number of pulses, pulse length, and pulse energy, on the structural and magnetic properties of GaMnAs. Using SQUID magnetometry, we revealed a strong decrease of the saturation magnetization with increasing number of pulses. HR-XRD-measurements revealed a lattice expansion normal to the surface after implantation. PLA leads either to a strain decrease (1 pulse) or even to a strain over compensation (10 pulses). We conclude that Mn implantation into GaAs followed by PLA is not sufficient for increasing the TC in GaMnAs. In addition, the drawback of the Mn implantation is the loss of As from the GaAs surface as detected by means of Auger electron spectroscopy. Heat transfer calculations and coimplantation with suitable elements are possible approaches to enhance the properties of GaMnAs.