Cabral Luís, Aragón Fermin H, Villegas-Lelovsky Leonardo, Lima Matheus P, Macedo Waldemar A A, Da Silva Juarez L F
Departamento de Física , Universidade Federal de São Carlos , 13565-905 São Carlos , São Paulo , Brazil.
Núcleo de Física Aplicada, Instituto de Física , Universidade de Brasília , DF, Brasília 70910-900 , Brazil.
ACS Appl Mater Interfaces. 2019 Jan 9;11(1):1529-1537. doi: 10.1021/acsami.8b14736. Epub 2018 Dec 28.
Tuning the magnetic properties of materials is a demand of several technologies; however, our microscopic understanding of the process that drives the enhancement of those properties is still unsatisfactory. In this work, we combined experimental and theoretical techniques to investigate the handling of magnetic properties of FeCo thin films via the thickness-tuning of a gold film used as an underlayer. We grow the samples by the deposition of polycrystalline FeCo thin films on the Au underlayer at room temperature by a magnetron sputtering technique, demonstrating that the lattice parameter of the sub-20 nm thickness gold underlayer is dependent on its thickness, inducing a stress up to 3% in sub-5 nm FeCo thin films deposited over it. Thus, elastic-driven variations for the in-plane magnetic anisotropy energy, K, up to 110% are found from our experiments. Our experimental findings are in excellent agreement with ab initio quantum chemistry calculations based on density functional theory, which helps to build up an atomistic understanding of the effects that take place in the tuning of the magnetic properties addressed in this work. The handling mechanism reported here should be applied to other magnetic films deposited on different metallic underlayers, opening possibilities for large-scale fabrication of magnetic components to be used in future devices.
调整材料的磁性是多种技术的需求；然而，我们对驱动这些特性增强过程的微观理解仍不尽人意。在这项工作中，我们结合实验和理论技术，通过对用作底层的金膜进行厚度调整来研究FeCo薄膜磁性的调控。我们通过磁控溅射技术在室温下在金底层上沉积多晶FeCo薄膜来生长样品，结果表明厚度小于20nm的金底层的晶格参数取决于其厚度，在沉积于其上的厚度小于5nm的FeCo薄膜中会产生高达3%的应力。因此，我们的实验发现面内磁各向异性能量K的弹性驱动变化高达110%。我们的实验结果与基于密度泛函理论的从头算量子化学计算结果非常吻合，这有助于建立对这项工作中磁性调控所发生效应的原子层面理解。这里报道的调控机制应适用于沉积在不同金属底层上的其他磁性薄膜，为未来器件中使用的磁性元件的大规模制造开辟了可能性。
