1. Current-driven perpendicular magnetization switching in Ta/CoFeB/[TaOx or MgO/TaOx] films with lateral structural asymmetry.
- Author
-
Guoqiang Yu, Li-Te Chang, Akyol, Mustafa, Upadhyaya, Pramey, Congli He, Xiang Li, Wong, Kin L., Amiri, Pedram Khalili, and Wang, Kang L.
- Subjects
- *
TANTALUM compounds , *MAGNESIUM compounds , *MAGNETIZATION , *THIN films , *MAGNETIC tunnelling - Abstract
We study the current-driven perpendicular magnetization switching in Ta/CoFeB(wedge)/[TaOx or MgO/TaOx] devices with a lateral structural asymmetry introduced by a varying CoFeB thickness. In these devices, an in-plane current can generate a field-like torque and its corresponding effective magnetic field (HzFL) is out-of-plane, which can deterministically switch perpendicular magnetiza-tion at zero magnetic field. Experimental results indicate that the method used for breaking lateral structural symmetry greatly affects the resulting field-like torque, and that the gradient of perpen-dicular anisotropy, resulting from the CoFeB thickness variation, is not by itself sufficient to give rise to the current-induced HzFL. Analysis of the oxidation gradient at the CoFeB/TaOx interface indicates that the oxidation gradient may play a more important role than the gradient of magnetic anisotropy for the generation of HzFL. For practical applications, the demonstration of perpendicular magnetization switching in Ta/CoFeB(wedge)/MgO/TaOx devices potentially allows for using MgO-based magnetic tunnel junctions for readout in three-terminal memory devices without the need for external magnetic fields [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF