Magnetic and Crystallographic Interactions of Alternately Deposited Fe and Al ultra-thin Layers

Abstract

ABSTRACTMultilayered films consisting of ferromagnetic Fe and nonmagnetic Al layers were prepared by using ion beam sputtering, and the relationships between their crystallographic characteristics and soft magnetic properties have been investigated in detail.The periodicity of the multilayered films was confirmed for various layer thicknesses (ΔFe and ΔA1) above 10Å from their X-ray diffraction peaks at low angle. When ΔFe decreased along with ΔA1 from 100Å, the coercivity Hc decreased and showed a minimum of 1.5 Oe at layer thicknesses of 20Å, but at the same time, the saturation magnetization 4πMs which was estimated from total thickness of the Fe layers decreased from 20 kG and showed drastic decrease at ΔFe below 10Å. For ΔFe above 100Å, 4πMs was constant around 20 kG without dependence on ΔA1. When ΔAl was changed for AFe of 100Å, the values of Hc had a interesting relationship with the crystallite orientation in Fe layers. Namely, the preferentially oriented planes of α-Fe crystallites changed from (110) to (200) in the case of Al layer thinner than 15Å and Hc showed a minimum below 4 Oe for ΔAl in this transition range of crystallite orientation, while 4πMs of all Fe layers themselves was kept at 20 kG. Taking into consideration that the nearest atomic distance of fcc Al and the lattice constant of bcc Fe is almost the same, these results may be caused by crystallographical interaction at the interfaces between Fe and Al layers.