Regensburg 2000 – wissenschaftliches Programm

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AM: Magnetismus

AM 13: Postersitzung: Dünne Schichten (1–22), Magnetowiderstand (23–40), Phasenübergänge (41–55), Mikromagnetismus (56–68), Spektroskopie (69–77), Nanokristalline Materialien (78–82), Anisotropie (83–86), Schmelzen (87–90), Weitere Bereiche (91–100)

AM 13.40: Poster

Dienstag, 28. März 2000, 16:00–20:00, A

Anomalous Hall effect revisited — •Patrick Bruno and Adeline Crépieux — Max-Planck-Institut fúr Mikrostrukturphysik, Halle

The anomalous Hall effect of ferromagnets is traditionally described in terms of 2 different processes, both originating from the spin-orbit coupling. The first process is the skew-scattering, which gives a contribution to the Hall resistivity proportional to the resistivity; the second process is the side-jump, which gives a contribution to the Hall resistivity proportional to the square of the resistivity. The discussion of the anomalous velocity giving rise to the side-jump is often very obscure in the literature, and its interpretation is partially erroneous. We show that it follows directly from the definition of the velocity operator, within the Pauli formalism, which yields an anomalous velocity giving rise to the side-jump. In addition, there is apparently a discrepancy between the approach based upon the Pauli hamiltonian in which the side-jump arises naturally as a consequence of the anomalous velocity, and the approach based upon the Dirac hamiltonian in which there is no anomalous velocity term. We solve the paradox by showing explicitely that the two approaches nevertheless give the same results in the weakly relativistic limit.