1. Effect of the oxide layer on current-induced spin-orbit torques in Hf|CoFeB|MgO and Hf|CoFeB|TaOx structures.
- Author
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Akyol, Mustafa, Alzate, Juan G., Guoqiang Yu, Upadhyaya, Pramey, Wong, Kin L., Ekicibil, Ahmet, Amiri, Pedram Khalili, and Wang, Kang L.
- Subjects
OXIDE coating ,HAFNIUM compounds ,TANTALUM oxide ,RASHBA effect ,ELECTRIC potential ,MAGNETIZATION ,FERROMAGNETIC materials ,SPIN Hall effect - Abstract
We study the effect of the oxide layer on the current-induced spin-orbit torques (SOTs) in perpendicularly magnetized Hf|CoFeB|MgO (MgO-capped) or Hf|CoFeB|TaO
x (TaOx -capped) structures. The effective fields corresponding to both the field-like and damping-like current-induced SOTs are characterized using electric transport measurements. Both torques are found to be significantly stronger in MgO-capped structures than those in TaOx -capped structures. The difference in fieldlike and damping-like SOTs in the different structures may be attributed to the different Rashbalike Hamiltonian, arising from the difference in the electric potential profiles across the oxide| ferromagnet interfaces in the two cases, as well as possible structural and oxidation differences in the underlying CoFeB and Hf layers. Our results show that the oxide layer in heavymetal |ferromagnet|oxide trilayer structures has a very significant effect on the generated SOTs for manipulation of ferromagnetic layers. These findings could potentially be used to engineer SOT devices with enhanced current-induced switching efficiency. [ABSTRACT FROM AUTHOR]- Published
- 2015
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