Effects of Mn clustering on ferromagnetism in (Ga,Mn)As
نویسندگان
چکیده
The magnetic interactions of substitutional Mn clusters in (Ga,Mn)As are investigated using density-functional total-energy supercell calculations within the projector augmented-wave method. Magnetic coupling strength values are directly calculated from the parallel and antiparallel spin alignments, and then used to estimate the Curie temperature TC. The magnetic interactions both inside the clusters and between consequent clusters are investigated. We find that the ferromagnetic coupling inside the clusters is considerably larger than the coupling between two distant clusters, and that therefore the cluster–cluster magnetic coupling strength will determine the TC of the material. Our cluster–cluster TC values agree closely with experimental ones. r 2005 Elsevier B.V. All rights reserved. PACS: 75.50.Pp; 85.75. d
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