Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 26: III-V semiconductors I
HL 26.4: Vortrag
Dienstag, 26. Februar 2008, 16:30–16:45, EW 202
Magnetic circular dichroism of Cr and Gd doped GaN — •David Wenzel1,4, Klaus Schmalbuch1,4, Bernd Beschoten1,4, Gernot Güntherodt1,4, Nicoleta Kaluza2,4, Yong Suk Cho2,4, Hilde Hardtdegen2,4, Thomas Schäpers2,4, Martin Röver3,4, Jörg Malindretos3,4, and Angela Rizzi3,4 — 1II. Physikalisches Institut, RWTH Aachen, Templergraben 55, 52056 Aachen — 2Institut für Bio- und Nanosysteme IBN-1 Forschungszentrum Jülich, 52425 Jülich — 3IV. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen — 4Virtuelles Institut für Spinelektronik (VISel), Aachen-Jülich-Göttingen
We have investigated magnetic properties of Cr and Gd doped GaN epilayers grown by MOVPE and MBE, respectively. Ferromagnetism is observed in 0.1% Cr-doped samples with Curie temperatures exceeding 600 K.
Magnetic circular dichroism (MCD) has been studied in order to probe the involved magnetic states and to reveal the nature of the magnetic exchange interaction.
The Cr doped samples show large MCD at the band edge, which is typical for diluted magnetic semiconductors. In addition, there is a large MCD between 1.9 eV and 2.3 eV.
Similar spectral features are observed in Gd doped samples with doping concentrations up to 0.1% suggesting that the MCD is not directly linked to the magnetic dopants.
Work supported by HGF and by DFG through SPP 1133