真空退火对L1_0-CoPt薄膜结构、磁性及表面形貌的影响

本文利用磁控溅射的方法制备了L1_0-CoPt薄膜,研究了不同退火条件对薄膜结构、磁性以及表面形貌的影响.通过优化退火温度、保温时间以及升温速率,制备出了具有大矫顽力、高矩形比、粗糙度小的垂直各向异性L1_0-CoPt薄膜.实验发现,较高的退火温度有利于克服CoPt薄膜有序化转变所需要的能量,同时适当延长退火时间可以提高CoPt薄膜的扩散系数,从而促使无序相fcc转化为L1_0有序相fct结构.此外,退火过程中减缓升温速率可以有效减小薄膜粗糙度,从而形成平整连续膜.

The effect of vacuum annealing on the structure, magnetism and surface topography of CoPt thin films

Abstract: In this paper, the effects of different annealing conditions on the structure, magnetism, and surface topography were studied in the L10-CoPt films deposited on thermal oxidized Si substrates by using magnetron sputtering. By optimizing the annealing temperature, time and heating rate, the perpendicular anisotropic L10-CoPt films with large coercivity, high squareness ratio, and small roughness were prepared. It is found that the higher annealing temperature is favorable to overcome the energy required for the ordering of CoPt films, and the diffusion coefficient of CoPt thin films can be improved by opportunely increasing the annealing time, which can promote the transformation of CoPt from disordered fcc phase into ordered fct phase. In addition, in the process of annealing, the film roughness can be improved effectively by reducing the heating rate, resulting into continuous and smooth films.