Fachgruppe Nanostrukturierte Materialien    


Publikationen
 
Home

Lehre
 Vorlesungen & Semin.
 Angebote f. Studenten

Forschung
 Themen
 Projekte
 Publikationen

Labore/Techniken
Anschrift
 Ausstattung
Röntgenbeugung

Mitarbeiter
 Übersicht
 offene Stellen

Links
 Universität Halle
 Institut für Physik
 IZM
 Andere Links

Institut f. Physik
FG Nanostrukturierte Materialien
Martin-Luther-Universitat
Halle-Wittenberg
Von-Danckelmann-Platz 3,
D-06120 Halle, Germany

Tel.:  +49 345 55 25321
Fax.: +49 345 55 27034

[Veröffentlichungen] [Patente] [Graduierungsarbeiten] [Berichte] [Poster]
Abstract

F. Kronast, R. Ovsyannikov, A. Vollmer, H.A. Dürr, W. Eberhardt, P. Imperia, D. Schmitz, G.M. Schott, C. Ruester, C. Gould, G. Schmidt, K. Brunner, M. Sawicki, L.W. Molenkamp
Mn 3d electronic configurations in (Ga1-xMnx)As ferromagnetic semiconductors and their influence on magnetic ordering
Phys. Rev. B 74 (2015-02-24 14:06:51), 235213

We applied x-ray absorption spectroscopy and x-ray magnetic circular dichroism (XMCD) at the Mn 2p?3d resonances to study the Mn 3d electronic configuration and the coupling of Mn 3d magnetic moments in various Ga1?xMnxAs films. The homogeneity of the Mn depth profile throughout the Ga1?xMnxAs film was tested by additional structure-sensitive x-ray resonant reflectivity measurements. In all investigated Ga1?xMnxAs films the electronic and magnetic configuration of the Mn impurities varies throughout the Mn-doped layer. This inhomogeneity is caused by the surface segregation of nonferromagnetic Mn in a d5 configuration. X-ray resonant reflectivity data show that the accumulation of nonferromagnetic Mn near the surface is strongly enhanced by low-temperature annealing. By XMCD we identified the Mn species responsible for the long-range ferromagnetic coupling. It is characterized by an Mn 3d5?3d6 mixed-valence acceptor state that is unchanged at all investigated Mn concentrations, ranging from 1% to 6%. Additional nonferromagnetic Mn occurs in the bulk of high-concentration samples. We discuss a model in which the latter is due to antiferromagnetic Mn-Mn nearest-neighbor pairs.

http://journals.aps.org/prb/abstract/10.1103/PhysRevB.74.235213
Impressum Copyright ©  Center of Materials Science, Halle, Germany. All rights reserved.