Husain Sajid, Akansel Serkan, Kumar Ankit, Svedlindh Peter, Chaudhary Sujeet
Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India.
Ångström Laboratory, Department of Engineering Sciences, Box 534, SE-751 21 Uppsala, Sweden.
Sci Rep. 2016 Jun 30;6:28692. doi: 10.1038/srep28692.
The influence of growth temperature Ts (300-773 K) on the structural phase ordering, static and dynamic magnetization behaviour has been investigated in ion beam sputtered full Heusler alloy Co2FeAl (CFA) thin films on industrially important Si(100) substrate. The B2 type magnetic ordering is established in these films based on the clear observation of the (200) diffraction peak. These ion beam sputtered CFA films possess very small surface roughness of the order of subatomic dimensions (<3 Å) as determined from the fitting of XRR spectra and also by AFM imaging. This is supported by the occurrence of distinct Kiessig fringes spanning over the whole scanning range (~4°) in the x-ray reflectivity (XRR) spectra. The Gilbert damping constant α and effective magnetization 4πMeff are found to vary from 0.0053 ± 0.0002 to 0.0015 ± 0.0001 and 13.45 ± 00.03 kG to 14.03 ± 0.04 kG, respectively. These Co2FeAl films possess saturation magnetization ranging from 4.82 ± 0.09 to 5.22 ± 0.10 μB/f.u. consistent with the bulk L21-type ordering. A record low α-value of 0.0015 is obtained for Co2FeAl films deposited on Si substrate at Ts ~ 573 K.
研究了生长温度Ts（300 - 773 K）对在工业上重要的Si(100)衬底上离子束溅射的全赫斯勒合金Co2FeAl（CFA）薄膜的结构相序、静态和动态磁化行为的影响。基于对（200）衍射峰的清晰观察，确定这些薄膜中存在B2型磁有序。根据XRR光谱拟合以及原子力显微镜成像测定，这些离子束溅射的CFA薄膜具有亚原子尺寸量级（<3 Å）的非常小的表面粗糙度。X射线反射率（XRR）光谱中在整个扫描范围（~4°）出现明显的基塞格条纹证明了这一点。发现吉尔伯特阻尼常数α和有效磁化强度4πMeff分别从0.0053±0.0002变化到0.0015±0.0001，以及从13.45±00.03 kG变化到14.03±0.04 kG。这些Co2FeAl薄膜的饱和磁化强度范围为4.82±0.09至5.22±0.10 μB/f.u.，与体相L21型有序一致。在Ts ~ 573 K下沉积在Si衬底上的Co2FeAl薄膜获得了创纪录的低α值0.0015。
