Berlin 2012 – wissenschaftliches Programm
MA 18.7: Vortrag
Dienstag, 27. März 2012, 11:15–11:30, H 0112
Magnetism in Phase Change Materials Doped with Magnetic Impurities — •Wei Zhang1, Yan Li1,2, and Riccardo Mazzarello1,2 — 1Institute for Theoretical Solid State Physics, RWTH Aachen, Aachen, Germany — 2JARA Fundamentals of Future Information Technology, Aachen, Germany
Chalcogenide phase-change materials undergo fast and reversible transitions between the amorphous and crystalline phase upon heating. This property is exploited in rewritable optical discs and nonvolatile phase-change memories, which are based on the strong optical and electronic contrast between the two phases respectively. Recently, phase change materials doped with magnetic impurities have drawn interest from both experimental and theoretical sides. In this work, we investigate the structural, electronic and magnetic properties of Ge2Sb2Te5, a prototypical phase-change material, doped with several types of magnetic impurities, namely Cr, Mn, Co, Ni, by ab initio simulations. Both amorphous and crystalline (hexagonal and cubic rocksalt) phases of Ge2Sb2Te5 were considered. We show that, when Ge2Sb2Te5 is doped with Cr or Mn, the system displays a strong magnetic contrast between the crystalline phases and the amorphous phase. This behavior is similar to that of Fe-doped Ge2Sb2Te5, which was recently investigated experimentally and theoretically. On the contrary, Ge2Sb2Te5 doped with Co or Ni turns out to be non-magnetic in the amorphous phase. Our results indicate that Cr and Mn impurities can be used to dope Ge2Sb2Te5, with the goal of exploiting the phase-change behavior for magnetic switching applications.