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Spin backflow and ac voltage generation by spin pumping and the inverse spin Hall effect
1Kavli Institute of NanoScience, Delft University of Technology, 2628 CJ Delft, The Netherlands.
Physical Review Letters
|June 11, 2013
Summary
Researchers computed alternating current (ac) inverse spin Hall effect (ISHE) voltages larger than direct current (dc) signals. Understanding spin backflow is essential for accurately measuring ISHE voltages in spintronic devices.
Area of Science:
- Spintronics
- Condensed Matter Physics
- Materials Science
Background:
- Spin currents generated by precessing ferromagnets exhibit both constant and rotating polarization components.
- The constant component induces a direct current (dc) voltage via the inverse spin Hall effect (ISHE), a routinely detected phenomenon.
- The rotating component's contribution to ISHE voltages remains less explored.
Purpose of the Study:
- To theoretically compute alternating current (ac) ISHE voltages generated by precessing ferromagnets.
- To compare the magnitude of ac ISHE voltages with existing dc ISHE signals.
- To identify optimal material combinations and conditions for observing these ac ISHE voltages.
Main Methods:
- Theoretical computation of spin current dynamics and resulting ISHE voltages.
- Analysis of various ferromagnet-normal metal material combinations.
- Investigating the role of spin backflow in parameter extraction.
Main Results:
- Calculated ac ISHE voltages significantly exceeding dc ISHE signals across diverse material systems.
- Identified specific conditions favoring the observation of large ac ISHE voltages.
- Demonstrated the critical importance of considering spin backflow for accurate parameter distillation from ISHE measurements.
Conclusions:
- Ac ISHE voltages offer a promising avenue for enhanced signal detection in spintronic devices.
- Optimizing material selection and understanding spin dynamics are key to leveraging ac ISHE signals.
- Accurate characterization of spintronic devices necessitates accounting for spin backflow in both dc and ac ISHE measurements.
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