RESEARCH ON MAGNETOVOLUME EFFECT AND INTERSTITIA ATOMS

典型铁基三种因瓦合金的X射线漫散射测量铁镍合金，制备了Fe-Pt和Fe-Pd合金，在Fe-Pt因瓦合金中没有观察到反常漫散射，在Fe-Pd因瓦合金中观察到盘状漫散射，在Fe-Ni因瓦合金中观察到沿着Oll-发现这种异常的起源是由沿沿着Oll方向的剪切应力引起的。平面，其通过Fe原子在小的局部区域中的小位移通过磁体积效应产生，在该小的局部区域中，Fe浓度是丰富的，并且状态正好在马氏体相变之前。从fcc相到bee相的转变在低温下发生，这种小位移用其他方法都没有检测到，只有目前的X射线漫散射测量成功地通过Fe原子的大磁体积效应观察到，用3d电子的铁磁性带理论解释了这一现象，并讨论了离子束辐照对铁磁性的影响。基础非晶铁磁合金的研究，并改善软磁性能，如高磁导率和低磁导率，这一结果被解释为感生磁各向异性与非晶合金在辐照初期所继承的原始磁各向异性的竞争。此外，从高压下的磁性测量结果来看，磁性原子在与间隙原子相同的条件下表现出较大的磁体积效应，这一结果也用3d电子的铁磁能带理论进行了解释.

Measurements of the X-ray diffuse scattering in typical Fe-base three Invar alloys ; Fe-Ni, Fe-Pt and Fe-Pd alloys were made.In Fe-Pt Invar alloy no anomaly in diffuse scattering was observed.In Fe-Pd Invar alloy a disc shape diffuse scattering was observed.In Fe-Ni Invar alloy a streek-like anomalous diffuse scattering was observed along Oll-direction.The origin of this anomaly is found to be caused by a shear stress along Oll-plane which is generated through the magnetovolume effect by small displacements of Fe atoms in a small local region where the Fe concentration is rich and the state is just before the martensitic transformation from fcc to bee phase takes place at low temperature.This type of small displacement was not detected by using any other method, and only the present X-ray diffuse scattering measurement has been successful to observe it through the large magnetovolume effect of Fe atoms, which is explained by using a ferromagnetic band theory of 3d electrons.The effect of ion beam irradiations on fe-base amorphous ferromagnetic alloys has been investigated, and an improvement of soft magnetic properties, such as high permeability and low coercivity, has been observed at an early stage of the irradiations.This result was explained as a competition of induced magnetic anisotropy with the original one which an amorphous alloy is inherited at the stage of rapid quenching.Furthermore, from the magnetic measurements under high pressures, magnetic atoms under the same condition as interstitial atoms show a large magnetovolume effect.This result was also explained by the ferromagnetic band theory of 3d electrons.