RESEARCH ON MAGNETOVOLUME EFFECT AND INTERSTITIA ATOMS

点击翻译按钮获取中文摘要

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.