Influence of the thickness of the carbon layer on the magnetization and structure of Fe/C multilayers

摘要

Multilayered films of a heavy metal and carbon have long been investigated. Major interest arises from the use of multilayers as soft X-ray monochromators and reflectors [1,2]. Studies have shown that the X-ray reflectance of the multilayers and their stability over time are determined by the extent of any interfacial reaction, including diffusion, amorphiza-tion or compound formation. In addition to the X-ray optical characteristics, magnetic properties of multilayer Fe/C, Ni/C and Co/C have been studied [3-7]. In particular, Fe/C multilayer films show good soft-magnetic properties and nearly zero magnetostriction. These properties are suitable for the application to thin-film heads. Studies have revealed that amorphous alloy or carbide layers are formed at metal-amorphous carbon interfaces, and magnetic properties are strongly influenced by these interfaces. Changes of structure of the interfaces of Fe/C multilayers with the Fe layer thickness have been noticed in some of the reported experiments, although the influence of the C layer thickness on the structure and magnetic properties, such as magnetization, of the multilayers has not been reported so far to our knowledge. In this letter we report the variation of magnetization and structure of Fe/C multilayers with individual carbon layer thickness.