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Inversion of ferromagnetic proximity polarization by MgO interlayers
1Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA.
Physical Review Letters
|July 23, 2008
Summary
We studied spin-dependent reflection in Fe/MgO/GaAs using optical measurements. Ferromagnetic proximity polarization (FPP) initially increased with MgO thickness but reversed sign, indicating an interfacial bonding effect.
Area of Science:
- Spintronics
- Materials Science
- Solid-State Physics
Background:
- Ferromagnetic proximity polarization (FPP) is crucial for spintronic devices.
- Understanding interfacial effects in heterostructures is key to controlling spin properties.
Purpose of the Study:
- Investigate spin-dependent reflection properties in Fe/MgO/GaAs heterostructures.
- Analyze the influence of MgO thickness on ferromagnetic proximity polarization (FPP).
- Determine the mechanism behind the observed FPP sign reversal.
Main Methods:
- Utilized optical pump-probe measurement techniques.
- Fabricated Fe/MgO/GaAs heterostructures with varying MgO layer thicknesses.
- Performed intensity-dependent measurements of FPP.
Main Results:
- Observed an initial enhancement of FPP for MgO thickness below 2.0 Å.
- Detected an unexpected sign reversal of FPP at approximately 5.0 Å MgO thickness.
- Identified two competing thresholds in the intensity dependence of FPP.
Conclusions:
- The sign inversion of FPP is strongly linked to interfacial bonding effects.
- Interfacial bonding plays a critical role in modulating spin polarization in Fe/MgO/GaAs.
- This finding offers insights for designing novel spintronic devices with tailored spin properties.
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