Magnetic and Structural Characteristics of Multi-layered Films Composed of Fe and Si Ultra-thin Layers

Fe and Si layers were deposited alternately by using ion beam sputtering apparatus and the relationship between crystal structure and soft magnetic properties of these multi-layered films have been investigated in detail. The clear periodicity of multi-layered films was confirmed even at the thicknesses of Fe and Si layers δFe and δSi as small as 8.5 Å.The saturation magnetization 4πMs for all Fe layers decreased with decrease of δFe and δSi, and the coercivity Hc of these films took minimum of 1.0 Oe at δFe of 8.5 Å.Such a significant decrease of 4TEMs may be attributed to the formation of nonmagnetic regions at both side of each Fe layers. The thickness of these nonmagnetic regions may be estimated at approximately 1.5 Å from the measured value of 4flMs. This thickness seems to be very small because it is almost equal to that of one monolayer of bcc α-Fe. The low Hc of the films with δFe and δSi of 8.5 Å may be due to the formation of ultra-fine crystallites in Fe layer by insertion of amorphous Si layer and the direct magnetostatic interaction among Fe layers.