Berlin 2012 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 36: Magnetic Heusler Compounds II

MA 36.7: Vortrag

Donnerstag, 29. März 2012, 11:45–12:00, H 1012

Improvement of the spin-transport properties by disorder — •Stanislav Chadov, Gerhard H. Fecher, and Claudia Felser — Max-Planck-Institut für Chemische Physik fester Stoffe, Dresden

In the context of electronic transport characteristics the presence of disorder is often treated as a severe destructive mechanism which must be reduced by any means. On the other hand, partial disorder opens a manifold of ways to affect the system, i.e. additional degrees of freedom to tune the electronic properties. As a constructive example, we will consider the spin-transport characteristics of Mn₃Ga Heusler compound tuned by the random Co-Mn substitution. Based on the first-principle calculations we show that the disorder-induced electron localization occurs only in one of the spin channels, by turning the material from a weakly spin-polarized metal to an almost half-metal in the sense of the spin-transport. In particular, the spin-polarization of the corresponding electron current does not depend neither on the magnetic moment of the compound nor on the spin polarization of the electrons at the Fermi energy. In addition, the proposed model explains the anomalous decrease of the magnetic moment observed experimentally in Mn_3−xCo_xGa (x<0.5) alloy series.