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Magnetic Tweezers for the Measurement of Twist and Torque
Published on: May 19, 2014
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Sagnac interferometry for high-sensitivity optical measurements of spin-orbit torque
Saba Karimeddiny1, Thow Min Jerald Cham1, Orion Smedley1
1Cornell University, Ithaca, NY 14850, USA.
Science Advances
|September 8, 2023
Summary
Sagnac interferometry offers superior signal-to-noise for magnetic imaging over the magneto-optical Kerr effect. This technique enables precise measurements of spin-orbit torque in magnetic thin films, aiding in validating electrical methods.
Area of Science:
- Condensed matter physics
- Spintronics
- Optical metrology
Background:
- Conventional magnetic imaging often uses the magneto-optical Kerr effect (MOKE).
- MOKE has limitations in signal-to-noise ratio, especially for certain magnetic anisotropies.
- Spin-orbit torque (SOT) is a key phenomenon in spintronics.
Purpose of the Study:
- To demonstrate the utility of Sagnac interferometry for quantitative magnetic measurements.
- To compare Sagnac interferometry with MOKE for imaging spin-orbit torque.
- To assess Sagnac interferometry's applicability to different magnetic anisotropy types.
Main Methods:
- Utilizing Sagnac interferometry for optical magnetic imaging.
- Investigating thin-film magnetic samples with perpendicular and in-plane anisotropy.
- Comparing Sagnac interferometry results with conventional MOKE measurements.
Main Results:
- Sagnac interferometry provides a significant signal-to-noise ratio improvement over MOKE.
- Quantitative measurements of current-induced magnetic deflections due to SOT are achievable.
- The technique is effective for both perpendicular and in-plane magnetic anisotropy samples.
Conclusions:
- Sagnac interferometry is a powerful tool for studying spin-orbit torque.
- It offers a reliable cross-check for electrical SOT measurement techniques.
- This method can help identify artifacts in existing electrical characterization methods.
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