npj Computational Materials

High-throughput design of perpendicular magnetic anisotropy at quaternary Heusler and MgO interfaces

Sicong Jiang, Kesong Yang

npj Computational Materials 9: 123(2023)

doi.org/10.1038/s41524-023-01079-4

Published online: 13 July 2023
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Abstract: Heusler alloys combined with MgO interfaces exhibit interfacial perpendicular magnetic anisotropy, making them attractive for energy-efficient spintronic technologies. However, finding suitable Heusler/MgO heterostructures with desired properties is challenging due to the vast range of compositions available and the complexity of interfacial structures, particularly for the emerging quaternary Heusler compounds. In this study, we report a high-throughput screening of quaternary-Heusler/MgO heterostructures for spintronic applications. By analyzing various materials descriptors, including formation energy, convex hull distance, magnetic ordering, lattice misfit, magnetic anisotropy constant, tunnel magnetoresistance, Curie temperature, and atomic site disordering, we identified 5 promising compounds out of 27,000 quaternary Heusler compounds. These compounds, namely IrCrAlTi, IrCrGaTi, IrMnZnTi, OsCrAlTa, and TaGaOsCr, show potential for designing energy-efficient perpendicular magnetic tunnel junctions. This work demonstrates an efficient approach using open quantum materials repositories, effective materials descriptors, and high-throughput computational techniques to accelerate the discovery of quaternary-Heusler-based functional materials.

摘要: 赫斯勒(Heusler)合金与氧化镁(MgO)界面形成的垂直磁各向异性在发展高效节能的自旋电子器件技术方面具有极大吸引力。然而，寻找具有特定材料性质的Heusler/MgO异质结构面临诸多挑战，因为Heusler合金具有非常广泛的元素组合（特别是对于新兴的四元Heusler化合物）以及复杂的界面结构。在这项研究中，我们利用高通量计算方法对四元Heusler/MgO界面结构进行了研究。通过分析多种材料描述符，包括材料形成能、convex hull distance、磁有序性、晶格匹配度、磁各向异性常数、隧道磁电阻、居里温度和原子位点无序度，我们在27,000个四元Heusler化合物中找到了5个有潜力的化合物，它们分别是IrCrAlTi、IrCrGaTi、IrMnZnTi、OsCrAlTa和TaGaOsCr。这些化合物有望在设计高效节能的垂直磁隧道结器件方面发挥重要的作用。此研究展示了一种基于开源量子材料数据库、材料描述符和高通量计算技术非常高效的材料筛选方法，有助于加速四元Heusler合金相关功能材料的研发过程。

Editorial Summary

Accelerate the discovery of Heusler-based functional materials with high-throughput calculations

As the rapid development of artificial intelligence and big data technologies, the dramatic increase in data volume and higher requirements for data processing speed have made the development of efficient and energy-saving data storage technologies and devices more crucial than ever. Traditional storage technologies face challenges in meeting these demands, thus the development of the next-generation efficient and energy-saving magnetic storage technology has garnered significant attention as a potential solution. The new magnetic storage technology should possess characteristics such as high data density, long-term data retention, and low power consumption. Among the key storage components, the vertical magnetic tunnel junction (MTJ) plays a critical role in the field of spintronics. Furthermore, the development of efficient and energy-saving data storage technology is equally important for breakthroughs in areas such as in-memory computing and neuromorphic computing. Achieving efficient and energy-saving magnetic storage technology and devices requires the development of novel materials. Heusler compounds, a collection of intermetallic compounds, exhibit a wide range of element tuning and controllable material properties. Particularly, their exceptional magnetic properties and potential topological electronic properties have made them a recent hotspot in innovative material design. In the development of the next-generation efficient and energy-saving magnetic storage device technology, the Heusler/MgO magnetic tunnel junctions with perpendicular magnetic anisotropy (p-MTJs) have drawn widespread research and attention due to their potential applications in efficient and energy-saving devices. However, due to the extensive range of element combinations in Heusler alloys, especially in emerging quaternary Heusler compounds, and the complexity of interface structures, finding suitable Heusler/MgO heterostructures with desired properties is challenging. It is quite difficult to identify Heusler compound/MgO combinations with the desired interface properties solely through experimental methods. Professor Kesong Yang's research group at the Department of NanoEngineering, University of California San Diego, utilized open quantum materials databases, effective material screening criteria, and high-throughput computational techniques to screen 27,000 quaternary Heusler compounds for spintronics applications and identified 5 promising candidates. The entire screening process is illustrated in Figure 1. During their bulk material screening, they not only considered detailed magnetic structures, including ferromagnetic, antiferromagnetic, and ferrimagnetic structures but also took into account the two competing quaternary phases of Heusler compounds (space group 215 and 129). They also considered the disorder in the quaternary phase since there may exist L21, B2, or D03-type disordered structures in quaternary compounds, which can affect material stability. In their heterostructure screening process, they calculated the magnetic anisotropy constant (Ki), tunnel magnetoresistance (TMR), and Curie temperature (TC). Finally, they obtained 5 candidate compounds that met the criteria of Ki > 1 mJ/m2, TMR > 80%, and TC > 300 K. These candidate compounds exhibited excellent properties and hold promise as potential materials for future spintronics applications.

高通量计算技术助力Heusler功能材料设计

伴随着人工智能与大数据技术的快速发展，数据量的急剧增加和对数据处理速度的更高要求，使得发展高效节能的数据存储技术与器件变得尤为重要。传统存储技术在满足这些需求方面面临挑战，因此，发展下一代高效节能的磁存储技术作为一种潜在的解决方案备受瞩目。新型磁存储技术应具有较高的数据密度、长期数据保存性和较低的功耗等特点，而其中的垂直磁隧道结（MTJ）作为重要的存储元件，在自旋电子学领域扮演着关键角色。此外，发展高效节能的数据存储技术对于实现in-memory computing（内存计算）以及neuromorphic computing（神经形态计算）等领域的突破同样具有重要意义。实现高效节能的磁存储技术与器件需要开发新型材料。Heusler化合物是一种金属间化合物集合，具有广泛的元素调节范围和可调控的材料性质，特别是其优异的磁学性质和可能的拓扑电子性质，使其再次成为近期创新材料设计的研究热点。特别事在发展下一代高效节能的磁存储器件技术中，具有垂直磁各向异性的Heusler/MgO磁隧道结（p-MTJs）因其在高效节能器件领域的潜在应用，引起了人们广泛的研究和关注。然而，由于赫斯勒合金的元素组合范围非常广阔，特别是新兴的四元Heusler化合物，以及界面结构的复杂性，寻找具有所需性质的合适Heusler/MgO异质结构具有挑战性。特别是单独通过实验的方法，想要找到具有所需界面性质的Heusler 化合物/MgO组合是十分困难的。加利福尼亚大学圣地亚哥分校纳米工程系杨可松(Kesong YANG)教授课题组，利用开源量子材料数据库、有效的材料筛选条件和高通量计算技术，从27000个四元结构的Heusler化合物中，为自旋电子应用筛选出了5个有前景的化合物。整个筛选过程如图1所示。在他们的体材料筛选过程中，他们不仅考虑了详细的磁结构，包括铁磁、反铁磁和亚铁磁结构，还考虑了四元Heusler化合物的两种竞争性四元相（空间群215和129）。同时，他们还考虑了四元相的无序性，因为通常在四元化合物中可能存在L21、B2或D03型的无序结构，这会影响材料的稳定性。在他们的异质结构筛选过程中，他们计算了磁各向异性常数（Ki）、隧道磁阻（TMR）和居里温度（TC）。最后，他们获得了5个满足Ki > 1 mJ/m2，TMR > 80%和TC > 300 K条件的候选化合物。这些候选化合物显示出优异的性质，可作为未来自旋电子应用的潜在材料。