Sarkar Soumya, Oh Saeyoung, Newton Peter J, Li Yang, Zhu Yiru, Ghani Maheera Abdul, Yan Han, Jeong Hu Young, Wang Yan, Chhowalla Manish
Department of Materials Science & Metallurgy, University of Cambridge, Cambridge, UK.
Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea.
Nat Electron. 2025;8(3):215-221. doi: 10.1038/s41928-024-01330-w. Epub 2025 Jan 20.
Graphene-based spintronic devices require efficient spin injection, and dielectric tunnel barriers are typically used to facilitate spin injection. However, the direct growth of ultrathin dielectrics on two-dimensional surfaces is challenging and unreliable. Here we report spin injection in graphene lateral spin valves using ferromagnetic van der Waals contacts of indium and cobalt (In-Co), and without the deposition of dielectric tunnel barriers. With this approach, we obtain magnetoresistance values of 1.5% ± 0.5% (spin signal around 50 Ω), which is comparable to state-of-the-art graphene lateral spin valves with oxide tunnel barriers, with a working device yield of more than 70%. By contrast, lateral spin valves with non-van der Waals contacts containing only cobalt are inefficient and exhibit, at best, a magnetoresistance of around 0.2% (spin signal around 3 Ω). The contact resistance of our ferromagnetic indium-cobalt van der Waals contacts is 2-5 kΩ, which makes them compatible with complementary metal-oxide-semiconductor devices.
基于石墨烯的自旋电子器件需要高效的自旋注入，通常使用介电隧道势垒来促进自旋注入。然而，在二维表面上直接生长超薄电介质具有挑战性且不可靠。在此，我们报道了在石墨烯横向自旋阀中使用铟和钴（In-Co）的铁磁范德华接触进行自旋注入，且无需沉积介电隧道势垒。通过这种方法，我们获得了1.5%±0.5%的磁电阻值（自旋信号约为50Ω），这与具有氧化物隧道势垒的先进石墨烯横向自旋阀相当，工作器件成品率超过70%。相比之下，仅含钴的非范德华接触的横向自旋阀效率低下，磁电阻最高约为0.2%（自旋信号约为3Ω）。我们的铁磁铟 - 钴范德华接触的接触电阻为2 - 5kΩ，这使其能够与互补金属氧化物半导体器件兼容。
