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Negative spin-polarization of SrRuO3
1Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
Physical Review Letters
|December 2, 2000
Summary
We discovered negative spin polarization in strontium ruthenium oxide (SrRuO3) using a novel tunneling measurement. This finding challenges existing models and opens new avenues for spintronic device research.
Area of Science:
- Condensed matter physics
- Materials science
- Spintronics
Background:
- Spin-polarized tunneling is a key technique for probing electron spin properties in materials.
- Strontium ruthenium oxide (SrRuO3) is a correlated oxide with potential applications in spintronics.
Purpose of the Study:
- To measure the spin polarization of SrRuO3 using Meservey-Tedrow style tunneling spectroscopy.
- To investigate the validity of the generalized Julliere model for negatively spin-polarized electrodes.
Main Methods:
- Meservey-Tedrow style spin-polarized tunneling spectroscopy.
- Fabrication of all-oxide tunnel junctions using SrTiO3 as a barrier layer.
Main Results:
- Strontium ruthenium oxide (SrRuO3) exhibits a negative spin polarization of -9.5%, a unique finding among materials studied with this technique.
- The magnetoresistance of a La(0.7)Sr(0.3)MnO3/SrTiO3/SrRuO3 tunnel junction was measured to test the Julliere model.
Conclusions:
- The observed negative spin polarization in SrRuO3 provides a new system for studying spin-dependent transport phenomena.
- Experimental results are consistent with the generalized Julliere model's prediction of inverse behavior for negatively spin-polarized electrodes.
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