Two-dimensional ferromagnetic superlattices
| Autor: | Ke Yang, Zhiming Liao, Hua Wu, Wen Zhang, Xufeng Kou, Faxian Xiu, Wenqing Liu, Ping Kwan Johnny Wong, Xiaoqian Zhang, Enze Zhang, Simon A. Morton, Andrew T. S. Wee, Jiabao Sun, Han Gao, Linfeng Ai, Alpha T. N'Diaye, Jin Zou, Yongbing Xu, Yunkun Yang, Shanshan Liu, Ce Huang, Zihan Li |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Crop and Pasture Production
Materials science (Fe3GeTe2/CrSb)n superlattice AcademicSubjects/SCI00010 Superlattice Materials Science 02 engineering and technology 2D ferromagnetic material 01 natural sciences Ferrimagnetism 0103 physical sciences Antiferromagnetism 010306 general physics Multidisciplinary Spintronics Condensed matter physics Magnetic circular dichroism 021001 nanoscience & nanotechnology Hysteresis Ferromagnetism proximity effect Curie temperature 2-inch Fe3GeTe2 film wafers room temperature 0210 nano-technology AcademicSubjects/MED00010 Research Article |
| Zdroj: | National Science Review National science review, vol 7, iss 4 |
| ISSN: | 2053-714X 2095-5138 |
| Popis: | Mechanically exfoliated two-dimensional ferromagnetic materials (2D FMs) possess long-range ferromagnetic order and topologically nontrivial skyrmions in few layers. However, because of the dimensionality effect, such few-layer systems usually exhibit much lower Curie temperature (TC) compared to their bulk counterparts. It is therefore of great interest to explore effective approaches to enhance their TC, particularly in wafer-scale for practical applications. Here, we report an interfacial proximity-induced high-TC 2D FM Fe3GeTe2 (FGT) via A-type antiferromagnetic material CrSb (CS) which strongly couples to FGT. A superlattice structure of (FGT/CS)n, where n stands for the period of FGT/CS heterostructure, has been successfully produced with sharp interfaces by molecular-beam epitaxy on 2-inch wafers. By performing elemental specific X-ray magnetic circular dichroism (XMCD) measurements, we have unequivocally discovered that TC of 4-layer Fe3GeTe2 can be significantly enhanced from 140 K to 230 K because of the interfacial ferromagnetic coupling. Meanwhile, an inverse proximity effect occurs in the FGT/CS interface, driving the interfacial antiferromagnetic CrSb into a ferrimagnetic state as evidenced by double-switching behavior in hysteresis loops and the XMCD spectra. Density functional theory calculations show that the Fe-Te/Cr-Sb interface is strongly FM coupled and doping of the spin-polarized electrons by the interfacial Cr layer gives rise to the TC enhancement of the Fe3GeTe2 films, in accordance with our XMCD measurements. Strikingly, by introducing rich Fe in a 4-layer FGT/CS superlattice, TC can be further enhanced to near room temperature. Our results provide a feasible approach for enhancing the magnetic order of few-layer 2D FMs in wafer-scale and render opportunities for realizing realistic ultra-thin spintronic devices. Utilizing proximity effect, we realize an effective and reliable approach to accomplish near-room-temperature (286.7 K) ferromagnetic order and double switching behavior in wafer-scale 4-layer-Fe3GeTe2/1.6-nm-CrSb superlattice. |
| Databáze: | OpenAIRE |
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