Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 36: Magnetic Semiconductors (jointly with MA)

HL 36.7: Talk

Tuesday, March 27, 2012, 11:15–11:30, H 0112

Magnetism in Phase Change Materials Doped with Magnetic Impurities — •Wei Zhang¹, Yan Li^1,2, and Riccardo Mazzarello^1,2 — 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.