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Spin-orbit-torque-driven multilevel switching in Ta/CoFeB/MgO structures without initialization.
- Source :
-
Applied Physics Letters . 1/28/2019, Vol. 114 Issue 4, pN.PAG-N.PAG. 4p. 2 Diagrams, 3 Graphs. - Publication Year :
- 2019
-
Abstract
- Spin-orbit torque (SOT) has been proposed as an alternative writing mechanism for the next-generation magnetic random access memory (MRAM), due to its energy efficiency and high endurance in perpendicular magnetic anisotropic materials. However, the three-terminal structure of SOT-MRAM increases the cell size and consequently limits the feasibility of implementing high density memory. Multilevel storage is a key factor in the competitiveness of SOT-MRAM technology in the nonvolatile memory market. This paper presents an experimental characterization of a multilevel SOT-MRAM cell based on a perpendicularly magnetized Ta/CoFeB/MgO heterostructure and addresses the initialization-free issue of multilevel storage schemes. Magneto-optical Kerr effect microscopy and micromagnetic simulation studies confirm that the multilevel magnetization states are created by changing a longitudinal domain wall pinning site in the magnet. The realization of robust intermediate switching levels in the commonly used perpendicularly magnetized Ta/CoFeB/MgO heterostructure provides an efficient way to switch magnets for low-power, high-endurance, and high-density memory applications. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00036951
- Volume :
- 114
- Issue :
- 4
- Database :
- Academic Search Index
- Journal :
- Applied Physics Letters
- Publication Type :
- Academic Journal
- Accession number :
- 134449520
- Full Text :
- https://doi.org/10.1063/1.5079313