SYNTHESIS PROCESS AND GIANT MAGNETIZATION OF INTERSTITIAL TYPE (Fe、Co)-(B、C、N) SINGLE CRYSTALS

我们研究了（Fe，Co）-（B，C，N）体系中存在Fe_（16）N_2超结构（α”相）的可能性。发现在后一体系中，B、C、N等原子均以有序方式存在于Fe、Co中。Fe倾向于通过这种夹杂物形成马氏体相，导致磁化强度增加。然而，没有证据表明该系统的上层建筑。通过发展高精度的X射线分析、磁化强度测量和样品合成方法，对Fe-N马氏体相及其超结构进行了研究，得到以下结果：1）通过高精度测定马氏体中超结构所占的比例，阐明了马氏体的磁化强度在2.4-3.0特斯拉范围内的任意值，它敏感地依赖于晶格的形变。迄今为止，许多研究小组所报道的相互矛盾的数据都可以用晶格形变的一致性来解释。2)进一步研究形成过程，α”的热稳定性和由此产生的晶格变形使我们得出这样的结论，即巨磁化强度很可能是从bcc到fcc类结构变形的结果，而与α”相关的大量磁化强度变化来自“高和低自旋态”。最后，我们得出结论，巨磁化是存在的，它是由在超结构形成过程中施加在晶格上的各向异性应力稳定的，我们可以结束最大的争议之一持续了25年。

We investigated possibility of existence of Fe16N2 superstructure (alpha" phase)、which has been claimed to have a giant magnetization (3.0 Tesla) but have been controversial、and other thinkable superstructures in (Fe、Co)-(B、C、N) system. We found that in the latter system B、C、N atoms are included in Fe、Co interstitially. Fe tends to form a martensite phase by this inclusion resulting in an increase of magnetization. However、no evidence of superstructure was obtained for this system. Through investigation of the martensite phase of Fe-N and its superstructure by developing high precision method of X-ray analysis、magnetization measurement and sample synthesis、the following results were obtained.1) We clarified by high precision determination of the rate of the superstructure included in the martensite that its magnetization takes any value in a range of 2.4-3.0 Tesla depending sensitively on deformation of the lattice. All data reported up to date by many research group which conflict with each other can be explained consistency in terms of the lattice deformation. 2) Further investigation of formation process、thermal stability and resultant lattice deformation of alpha" led us to the conclusion that it is highly possible that the giant magnetization is a result of the deformation from bcc to fcc like structure and the large variety of magnetization associated with alpha" is from 「the high and low spin state」 which has been found in the fcc Fe.Finally we conclude that the giant magnetization is in existence and it is stabilized by an anisotropic stress imposed on the lattice during formation of the superstructure and we could put an end to one of the largest controversy which lasted for these 25 years.