Local structure analysis of SmFe and TbFe

Yoneda, Yasuhiro   ; Abe, Hiroshi

TbFe and SmFe are well-known giant magnetostrictive materials and they show different behavior when Ar ions irradiated. Since SmFe and TbFe are the same crystal structure, the same mechanism of spontaneous magnetization should exist. The different ion irradiation effects may be caused by the different internal stress between SmFe and TbFe2 films. However, it has been difficult to analyze the internal strain in the amorphous films. The purpose of this article is to clarify the local structure of amorphous SmFe and TbFe and clarify the relationship between the ion irradiation effect and the magneticostrictive susceptivity. Structure analysis was carried out using synchrotron X-ray pair-distribution function method. The internal strain can be evaluated by the deviation between the amorphous and crystalline structures. The deviation of the TbFe was larger than that of the SmFe. Large deviation causes large internal strain, which is reduced by the ion irradiation.