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用电子衍射方法和Lorentz电子显微术观察了非晶态Gd-Co合金磁膜结构和磁畴的变化。薄膜在10~(-2)mmHg的低真空下作了为期二周的室温处理,也在5×10~(-7)mmHg的高真空下加热。发现低真空下作室温处理和高真空下加热都能使薄膜中发生相分离,而且薄膜的衍射强度峰形和磁畴图象均随之发生变化,Gd与Co原子间最近邻配位数明显下降,与此同时磁畴图象中的磁泡显著减少甚至消失,出现平面畴。这再次证实了非晶态Gd-Co合金磁膜各向异性与Gd,Co原子间最近邻配位数有一定联系,而且配位数能直观反映在衍射峰形上。加热至350℃时Co首先结晶,其主要组成为α-Co,并有少量β-Co。随着温度继续上升α-Co逐渐转变为β-Co。即使加热至950℃亦未见Co氧化,而Gd在晶化之前就严重氧化。在晶化的全过程中均未发现Gd-Co台金和金属Gd的痕迹。本文还给出了磁畴图象随温度的变化,并讨论了薄膜中的相分离和短程有序状态对磁各向异性的影响。
The changes of magnetic film structure and magnetic domains of amorphous Gd-Co alloy were observed by electron diffraction and Lorentz electron microscopy. The film was treated at room temperature for two weeks under a low vacuum of 10-2 mmHg and also under a high vacuum of 5x10-7 mmHg. It is found that the phase separation occurs in the film under the conditions of room temperature treatment under high vacuum and heating under high vacuum. The peaks of diffraction intensity and the images of the magnetic domains are changed. The nearest neighbor coordination number between Gd and Co atoms is obvious While at the same time, the magnetic bubble in the magnetic domain image significantly reduces or even disappears, and the planar domain appears. This again confirms the amorphous Gd-Co alloy magnetic film anisotropy and the Gd, Co atoms nearest neighbor coordination number has a certain relationship, and the coordination number can be directly reflected in the diffraction peak shape. When heated to 350 ° C, Co crystallizes first and its main composition is α-Co with a small amount of β-Co. As the temperature continues to rise, α-Co gradually changes to β-Co. Even when heated to 950 ° C, no Co oxidation was observed, and Gd was heavily oxidized prior to crystallization. In the whole process of crystallization, no traces of Gd-Co gold and metal Gd were found. This paper also gives the change of magnetic domain image with temperature, and discusses the influence of phase separation and short-range order on magnetic anisotropy.