Analysis of grain size in FePt films fabricated using remote plasma deposition
Analysis of grain size in FePt films fabricated using remote plasma deposition
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DOI：
10.1016/j.jmmm.2017.07.057
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发表时间：
2017-12
影响因子：
2.7
通讯作者：
D. Huskisson;Smaragda Zygridou;S. Haigh;C. Barton;P. Nutter;T. Thomson
中科院分区：
文献类型：
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作者：
D. Huskisson;Smaragda Zygridou;S. Haigh;C. Barton;P. Nutter;T. Thomson
远程等离子体溅射（RPS）提供了对用于存款薄金属膜的溅射参数的高度控制，并且已经证明了控制介质粒度分布的能力。窄粒度分布仍然是未来磁介质的关键要求。在这里，我们报告了一个全面的磁力，X射线衍射和透射电子显微镜研究RPS如何影响连续的，非偏析的L10 FePt薄膜的晶粒尺寸分布。这些提供了用于热辅助磁记录的模型介质，并且更一般地用于自旋电子器件，例如磁阻随机存取存储器和自旋扭矩振荡器，其中需要非常高的垂直磁晶各向异性。改变目标DC偏置电压（其在RPS中可以独立于等离子体产生而调谐）对于沉积的无序FePt的平均晶粒尺寸（6.5 ± 0.1 nm）不产生有意义的统计变化。在800 °C下退火产生了良好有序的L10相，但导致8.3-13.6 nm的平均晶粒尺寸增加，以及6.4-8.5 nm的显著更宽的晶粒尺寸分布。这些结果表明，虽然RPS是能够生产良好有序的L10 FePt薄膜，它不提供控制FePt的晶粒尺寸的优势，在其他薄膜系统中报道。
Remote plasma sputtering (RPS) offers a high degree of control over the sputtering parameters used to deposit thin metallic films and has demonstrated a capability to control the media grain size distribution. Narrow grain size distributions remain a key requirement for future magnetic media. Here we report a comprehensive magnetometry, X-ray diffraction and transmission electron microscopy study of how RPS affects the grain size distribution of continuous, non-segregated L10FePt thin films. These provide a model medium for heat-assisted magnetic recording and more generally for spintronic devices such as magnetoresistive random access memory and spin torque oscillators, where very high perpendicular magnetocrystalline anisotropy is required. Varying the target DC bias voltage, which in RPS can be tuned independently of the plasma generation, produces no meaningful, statistical change in average grain size, 6.5 ± 0.1 nm, for as-deposited, disordered FePt. Annealing at 800 °C creates the well-ordered L10phase but results in an increased average grain size of 8.3–13.6 nm, and a significantly wider grain size distribution of 6.4–8.5 nm. These results show that whilst RPS is capable of producing well-ordered L10FePt thin films, it does not offer an advantage in controlling the grain size of FePt, as reported in other thin film systems.