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Intrinsic versus extrinsic anomalous Hall effect in ferromagnets
Shigeki Onoda1, Naoyuki Sugimoto, Naoto Nagaosa
1Spin Superstructure Project, ERATO, Japan Science and Technology Agency, c/o Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan. sonoda@appi.t.u-tokyo.ac.jp
Physical Review Letters
|October 10, 2006
Summary
This study presents a unified theory for the anomalous Hall effect (AHE) in ferromagnetic metals. It reveals a crossover from extrinsic to intrinsic AHE driven by spin-orbit coupling and band structure.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Solid-State Physics
Background:
- The anomalous Hall effect (AHE) is a fundamental phenomenon in ferromagnetic metals.
- Understanding the interplay between extrinsic and intrinsic contributions to AHE is crucial for materials design.
- Previous theories often treated extrinsic and intrinsic mechanisms separately.
Purpose of the Study:
- To develop a unified theoretical framework for the anomalous Hall effect (AHE) in multiband ferromagnetic metals.
- To investigate the role of dilute impurities and spin-orbit interaction in AHE.
- To elucidate the crossover mechanism between extrinsic and intrinsic AHE.
Main Methods:
- Development of a unified theory applicable to multiband ferromagnetic systems.
- Ab initio calculations to determine intrinsic AHE contributions.
- Analysis of extrinsic skew scattering in the presence of dilute impurities.
Main Results:
- In the clean limit, extrinsic skew scattering dominates the AHE.
- A resonant enhancement of intrinsic AHE occurs near band anticrossings due to spin-orbit interaction.
- An extrinsic-to-intrinsic AHE crossover is identified when relaxation rates approach spin-orbit coupling strength.
Conclusions:
- The unified theory successfully explains the anomalous Hall effect in ferromagnetic metals with dilute impurities.
- Spin-orbit interaction plays a critical role in enhancing intrinsic AHE through nonperturbative effects.
- The findings provide insights into controlling AHE by tuning material properties and impurity concentrations.
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