33 research outputs found
Theory of the anomalous Hall effect from the Kubo formula and the Dirac equation
A model to treat the anomalous Hall effect is developed. Based on the Kubo
formalism and on the Dirac equation, this model allows the simultaneous
calculation of the skew-scattering and side-jump contributions to the anomalous
Hall conductivity. The continuity and the consistency with the
weak-relativistic limit described by the Pauli Hamiltonian is shown. For both
approaches, Dirac and Pauli, the Feynman diagrams, which lead to the
skew-scattering and the side-jump contributions, are underlined. In order to
illustrate this method, we apply it to a particular case: a ferromagnetic bulk
compound in the limit of weak-scattering and free-electrons approximation.
Explicit expressions for the anomalous Hall conductivity for both
skew-scattering and side-jump mechanisms are obtained. Within this model, the
recently predicted ''spin Hall effect'' appears naturally
X-Ray Analysis of Oxygen-induced Perpendicular Magnetic Anisotropy in Pt/Co/AlOx trilayer
X-ray spectroscopy measurements have been performed on a series of Pt/Co/AlOx
trilayers to investigate the role of Co oxidation in the perpendicular magnetic
anisotropy of the Co/AlOx interface. It is observed that high temperature
annealing modifies the magnetic properties of the Co layer, inducing an
enhancement of the perpendicular magnetic anisotropy. The microscopic
structural properties are analyzed via X-ray Absorption Spectroscopy, X-ray
Magnetic Circular Dichroism and X-ray Photoelectron Spectroscopy measurements.
It is shown that annealing enhances the amount of interfacial oxide, which may
be at the origin of a strong perpendicular magnetic anisotropy