CoFeB/MgO/CoFeB structures with orthogonal easy axes: perpendicular anisotropy and damping
H Głowiński1, A Żywczak2, J Wrona3
1Institute of Molecular Physics, Polish Academy of Sciences, ul. Smoluchowskiego 17, 60-179 Poznan, Poland.
Summary
We investigated the magnetic properties of CoFeB/MgO/CoFeB thin films, finding a nonlinear relationship between effective magnetization and g-factor asymmetry. Annealing caused changes in magnetic alignment but increased linewidth due to broadening.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Spintronics
Background:
- Understanding magnetic properties of thin films is crucial for spintronic device development.
- CoFeB/MgO heterostructures are promising for magnetic tunnel junctions.
Purpose of the Study:
- To characterize the Gilbert damping parameter, effective magnetization, and g-factor asymmetry in as-deposited and annealed CoFeB/MgO/CoFeB systems.
- To explore the relationship between these magnetic parameters.
Main Methods:
- Fabrication of bottom-CoFeB/MgO/top-CoFeB thin film heterostructures.
- Measurement of Gilbert damping parameter (α).
- Determination of effective magnetization ([Formula: see text]) and g-factor asymmetry ([Formula: see text]).
Main Results:
- As-deposited films showed a noncollinear magnetic configuration with orthogonal easy axes.
- [Formula: see text] exhibited a highly nonlinear dependence on g-factor asymmetry ([Formula: see text]).
- Gilbert damping (α) was similar for both CoFeB layers, but annealing led to collinear easy axes and increased linewidth due to inhomogeneous broadening.
Conclusions:
- The study reveals a complex interplay between magnetization, g-factor asymmetry, and damping in CoFeB/MgO systems.
- Annealing alters magnetic anisotropy but introduces broadening effects, impacting device performance.
- Nonlinear relationships observed offer insights for future spintronic material design.
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