Spin pumping in magnetic trilayer structures with an MgO barrier
A A Baker1,2, A I Figueroa2, D Pingstone3
1Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, OX1 3PU, United Kingdom.
Scientific Reports
|October 19, 2016
Summary
We studied magnetic trilayers with MgO barriers, finding unexpected oscillatory interlayer exchange coupling with increasing MgO thickness. This reveals potential for magnetic tunnel junction devices.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Spintronics
Background:
- Magnetic trilayer structures with insulating barriers are crucial for spintronic devices.
- Understanding interlayer exchange coupling (Aex) and damping is vital for device performance.
Purpose of the Study:
- To investigate the interaction mechanisms in magnetic trilayer structures with MgO barriers.
- To determine the influence of MgO barrier thickness on interlayer coupling and damping.
Main Methods:
- SQUID magnetometry and ferromagnetic resonance (FMR) for interlayer exchange coupling (Aex).
- Transmission electron microscopy (TEM) for barrier quality assessment.
- X-ray detected FMR for element-specific dynamic interactions.
Main Results:
- Observed unexpected oscillatory behavior of Aex with increasing MgO thickness (1-4 nm).
- Confirmed MgO barrier continuity via TEM, ruling out direct ferromagnetic layer contact.
- Found Gilbert damping largely independent of MgO thickness, indicating suppressed spin pumping.
- Detected a small dynamic exchange interaction contributing to coupled precession.
Conclusions:
- The study elucidates complex interaction mechanisms in MgO-based magnetic trilayers.
- Oscillatory coupling and dynamic interactions are key factors for device design.
- Results support the potential of spin pumping and spin transfer torque in magnetic tunnel junctions.
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