Regensburg 2010 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 26: Spin-controlled Transport II
HL 26.4: Talk
Tuesday, March 23, 2010, 14:45–15:00, H14
Cu-doped Nitrides: Spinaligner at room-temperature — •Philipp R. Ganz1,2, Christoph Sürgers1,3, and Daniel M. Schaadt1,2 — 1DFG-Center for Functional Nanostructures, Karlsruher Institute of Technology, 76131 Karlsruhe, Germany — 2Institut für Angewandte Physik, Karlsruher Institute of Technology, 76131 Karlsruhe, Germany — 3Physikalisches Institut, Karlsruher Institute of Technology, 76131 Karlsruhe, Germany
Nitride based spintronics is emerging as an interesting alternative to arsenide based spintronics. One reason for this strong interest is the long spin-lifetime in InN quantum dots which is shown to be temperature independent. For spin-injection into these quantum dots, a ferromagnetic spin-aligner which yields high spin-polarization at room-temperature is necessary. Copper doped nitrides are promising candidates as spin-aligners, because non-magnetic material is used, thereby avoiding confusing results due to magnetic clusters, as in the case of Maganese or Gadolinium doped nitrides. Theoretical predictions show the possibility of ferromagnetism and a high spin-polarization for Cu-doped GaN and AlN. A few experimental results have indicated ferromagnetism in both materials. We investigated and optimized the growth of Cu-doped GaN and AlN by plasma assisted molecular beam epitaxy on different substrates. Our Cu-doped films show ferromagnetic behaviour far above room temperature. The influence of growth parameters such as growth temperature, Cu to metal flux ratio and metal to nitrogen flux ratio on the magnetic properties was determined.