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 |