標題: Superparamagnetic ground state of CoFeB/MgO magnetic tunnel junction with dual-barrier
作者: Thanh-Nga Tran
Tu-Ngoc Lam
Yang, Chao-Yao
Lin, Wen-Chin
Chen, Po-Wen
Tseng, Yuan-Chieh
材料科學與工程學系
Department of Materials Science and Engineering
關鍵字: Magnetic random access memory;Magnetic tunnel junction;Perpendicular magnetic anisotropy;Spin-valve
公開日期: 1-Nov-2018
摘要: CoFeB/MgO-based magnetic tunnel junctions (MTJs) have considerable potential in magnetic random access memory (MRAM), thanks to their tunable perpendicular magnetic anisotropy (PMA). We found significant reduction of dead-layer by inserting additional MgO into the MTJ structure. Interface, electronic and transport characterizations were utilized to approach the modified magnetic properties driven by the dual-MgO structure in this work. The dual-MgO structure appeared to hinder boron (B) diffusion into the metallic layer and prevent capping-layer (Ta) penetration across the interface. This suppressed the dead-layer effect and promoted overall magnetization despite PMA degradation. A robust BOx phase that formed within the dual-MgO structure presented a superparamagnetic ground state. In the single-MgO structure, any reduction in the thickness of the CoFeB promoted PMA, albeit at the cost of spin-polarization. The dual-MgO structure could restore spin-polarization by preferentially populating spin electrons into Fe/Co minority states. X-ray magnetic spectroscopy and anomalous Hall effect suggest that, the dual-MgO differs from the single-MgO with a favorable longitudinal polarized spin-channel. This makes the dual-MgO structure applicable to applications requiring in-plane rather than out-of-plane sensing.
URI: http://dx.doi.org/10.1016/j.apsusc.2018.06.292
http://hdl.handle.net/11536/148022
ISSN: 0169-4332
DOI: 10.1016/j.apsusc.2018.06.292
期刊: APPLIED SURFACE SCIENCE
Volume: 457
起始頁: 529
結束頁: 535
Appears in Collections:Articles