Discipline of Metallurgy Engineering and Materials Science, School of Basic Sciences, Indian Institute of Technology (IIT) Indore, Indore, Madhya Pradesh 453552, India.
Nanoscale. 2018 Dec 21;10(47):22280-22292. doi: 10.1039/c8nr07429a. Epub 2018 Nov 22.
The primary research target of the rapidly evolving spintronic industry is to design highly efficient novel materials that consume very low power and operate with high speed. Main group based ferromagnetic half-metallic materials are very promising due to their long spin-relaxation time. In recent years, the discovery of superconducting state with high critical temperature in a magnesium based system (MgB) invigorated researchers due to its simple crystal structure and intriguing results, leading to its use as a good material for large scale application in electronic devices. Here, we report ferromagnetism and strong half-metallicity in another Mg-based system, which can be a promising material for spintronics based devices rather than for electronic devices (such as MgB). Based on the first principle calculations, we report here a series of magnetic half-metallic magnesium chloride based monolayers [MgδCl, MgδCl, and MgδCl (MgCl)]. This MgCl phase has a similar pattern as that in CrI, which has drawn remarkable attention worldwide as the first intrinsic 2D magnet. These magnesium chloride monolayer based systems are 100% spin-polarized, and promising for scattering-less transport due to strong half-metallicity and large spin-up gap (∼6.135-6.431 eV). The unusually large spin-up gap in our proposed system may shield spin current leakage even in nanoscale device. Further investigation explores a ferromagnetic ordering in MgδCl with a Curie temperature of 250 K, which makes the system viable for operation at temperatures slightly lower than the room temperature. High magnetic anisotropy energy (MAE) in MgδCl (452.84 μeV) indicates that the energy required to flip the spin is high, and therefore inhibits spin fluctuation. These results suggest a promising way to discover MgCl-based 2D spin valves, GMR, TMR and other spintronics devices.
自旋电子学产业的主要研究目标是设计高效的新型材料，这些材料需要消耗极低的功率并具有高速运行的特点。基于主族的铁磁半金属材料由于其较长的自旋弛豫时间而具有很大的应用潜力。近年来，在镁基体系（MgB）中发现了具有高温超导性的状态，由于其简单的晶体结构和有趣的结果，激发了研究人员的兴趣，使其成为电子器件中大尺寸应用的良好材料。在这里，我们报告了另一种基于镁的体系（MgB）中的铁磁性和强半金属性，它可以作为自旋电子学器件的有前途的材料，而不是电子器件（如 MgB）的材料。基于第一性原理计算，我们在此报告了一系列基于磁性半金属镁氯的单层[MgδCl、MgδCl 和 MgδCl（MgCl）]。这种 MgCl 相具有与 CrI 相似的结构，CrI 作为第一个本征二维磁体引起了全球的关注。这些基于镁氯单层的系统是 100%自旋极化的，由于强半金属性和大的自旋向上能隙（约 6.135-6.431eV），有望实现无散射传输。我们提出的体系中异常大的自旋向上能隙甚至可以屏蔽自旋电流泄漏，即使在纳米级器件中也是如此。进一步的研究探索了具有 250K 居里温度的 MgδCl 的铁磁有序，这使得该体系在略低于室温的温度下运行成为可能。MgδCl 中的高磁各向异性能（MAE）为 452.84μeV，表明翻转自旋所需的能量较高，因此抑制了自旋波动。这些结果表明了一种有前途的方法，可以发现基于 MgCl 的二维自旋阀、GMR、TMR 和其他自旋电子学器件。
