Effects of temperature gradients on magnetic anisotropy of SmCo based films
Effects of temperature gradients on magnetic anisotropy of SmCo based films
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DOI：
10.1016/j.jallcom.2021.162900
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发表时间：
2021-11
影响因子：
6.2
通讯作者：
L. Wei;Y.W. Zhang;Y. Gong;Y. Hong;Z. Qiu;L.Z. Zhao;X.L. Liu;X.F. Zhang;D.Y. Chen
中科院分区：
文献类型：
--
作者：
L. Wei;Y.W. Zhang;Y. Gong;Y. Hong;Z. Qiu;L.Z. Zhao;X.L. Liu;X.F. Zhang;D.Y. Chen
SmCo基永磁薄膜的磁各向异性通常通过引入缓冲层或加热衬底来控制。然而，由于缓冲层和SmCo层之间的界面应力/应变的范围较短，多层薄膜系统的设计是复杂的，并且SmCo的厚度受到限制。在这项工作中，温度梯度的影响，所产生的快速热处理（RTP），对SmCo基薄膜的磁各向异性进行了系统的研究。结果表明，沉积态薄膜为非晶态。RTP处理的膜的面外折射率与加热速率密切相关，其最佳值（2810 Oe）大于CTA（常规热退火）处理的膜的最佳值（1670 Oe）。对于RTP处理的薄膜，面内取向SmCo 5（200）和Sm 2Co 17（300）的特征衍射峰的强度降低，同时降低了粗糙度。此外，由于SmCo 5/Sm 2Co 17相的易磁化轴由面内逐渐向面外方向转变，RTP处理后薄膜的晶粒尺寸更细，磁畴对比度更强。结果表明，缩短退火时间的RTP处理有利于获得更细小的微观结构，改善SmCo基薄膜的面外磁各向异性。与传统方法相比，本工作提供了一种通过退火温度梯度来控制永磁薄膜磁各向异性的新方法。
The magnetic anisotropy of SmCo-based permanent magnetic thin films are generally controlled by introducing buffer layer or heating substrate. However, the design for the multi-layer thin film system is complicated and the thickness of SmCo is limited due to a short range of interfacial stress/strain between the buffer layer and SmCo layer. In this work, the effects of temperature gradients, generated by RTP (rapid thermal process), on the magnetic anisotropy of the SmCo-based films were systematically investigated. The results show that the as-deposited films exhibit amorphous state. The out-of-plane coercivity of RTP-treated films is strongly correlated with the heating rate, and its optimum value (2810 Oe) is larger than that of the CTA (conventional thermal annealing) treated films (1670 Oe). For the RTP-treated films, the intensity of characteristic diffraction peaks for in-plane oriented SmCo5(200) and Sm2Co17(300) decreases, together with reducing the roughness. Besides, the grain size is finer and the contrast of magnetic domains becomes stronger for the RTP-treated films due to that the easy axis of SmCo5/Sm2Co17phase gradually changes from in-plane to out-of-plane direction. It is suggested that the RTP treatment with a shorter annealing time has beneficial effects on obtaining finer microstructure and improving the out-of-plane magnetic anisotropy of the SmCo-based films. This work provides a novel way to control the magnetic anisotropy via annealing temperature gradients for permanent magnetic thin films, compared with conventional methods, to induce the magnetic anisotropy.