Asymmetric angular dependence of spin-transfer torques in CoFe/Mg-B-O/CoFe magnetic tunnel junctions
| Autor: | Tang, Ling, Xu, Zhi-Jun, Zuo, Xian-Jun, Yang, Ze-Jin, Gao, Qing-He, Linghu, Rong-Feng, Guo, Yun-Dong |
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| Rok vydání: | 2016 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics 119, 163902 (2016) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1063/1.4947527 |
| Popis: | Using a first-principles noncollinear wave-function-matching method, we studied the spin-transfer torques (STTs) in CoFe/Mg-B-O/CoFe(001) magnetic tunnel junctions (MTJs), where three different types of B-doped MgO in the spacer are considered, including B atoms replacing Mg atoms (Mg$_3$BO$_4$), B atoms replacing O atoms (Mg$_4$BO$_3$), and B atoms occupying interstitial positions (Mg$_4$BO$_4$) in MgO. A strong asymmetric angular dependence of STT can be obtained both in ballistic CoFe/Mg$_3$BO$_4$ and CoFe/Mg$_4$BO$_4$ based MTJs, whereas a nearly symmetric STT curve is observed in the junctions based on CoFe/Mg$_4$BO$_3$. Furthermore, the asymmetry of the angular dependence of STT can be suppressed significantly by the disorder of B distribution. Such skewness of STTs in the CoFe/Mg-B-O/CoFe MTJs could be attributed to the interfacial resonance states induced by the B diffusion into MgO spacer. The present investigation demonstrates the feasibility of effectively enhancing microwave output power in MgO based spin torque oscillator (STO) by doping the B atoms into MgO spacer. Comment: 8 pages, 8 figures |
| Databáze: | arXiv |
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