Přednášející: Josef Kudrnovský ( Oddělení teorie kondenzovaných látek, FZÚ AV ČR, v.v.i.)
Místo: Na Slovance, přednáškový sál v přízemí
Jazyk: anglicky
Pořadatelé:
Oddělení teorie kondenzovaných látek
Abstract
The anomalous Hall effect (AHE) represents an important example of a spin-orbit driven transport phenomenon in itinerant magnets known for many years. First-principles studies of specific materials have appeared for pure and ordered magnets only recently.
We present here a systematic approach to the AHE which allows to treat both ordered and disordered systems. It is based on the Bastin formulation of the relativistic transport which allows to treat both the Fermi-surface (depending on behavior at the Fermi energy) and Fermi-sea (depending on occupied states) terms on equal footing. The latter term was neglected in existing theories of the AHC in disordered alloys.
The developed formalism is tested on a broad range of magnetic alloys including ferromagnetic 3d transition metals (Fe, Co, Ni) and their random binary alloys (fcc-NiFe, bcc-FeSi, fcc-PdCo), diluted magnetic semiconductors (GaMnAs), as well as alloys with partial chemical long-range order (Pd-rich PdFe, ordering FePt, B2-FeRh) and chosen Heusler alloys. The emphasis is put on the anomalous Hall conductivity, but in chosen cases also related physical quantities like the residual resistivity and the anisotropic magnetoresistance will be discussed. Overall good agreement with available experimental data was obtained confirming the validity of the present theory.
Present talk is based on the formalism and applications published in recent papers:
[1] Phys. Rev. B 89 (2014) 064405,
[2] Phys.Rev. B 89 (2014) 224422,
[3] Nature Materials 13 (2014) 367,
[4] Phys.Rev. B 91 (2015) 014435, [5] Phys.Rev. B 92 (2015) 224421
(*) In collaboration with V. Drchal and I.Turek
Copyright © 2008-2014, Fyzikální ústav AV ČR, v. v. i.
