Magnetic decoupling in sputtered Fe/Si superlattices and multilayers

Abstract

A series of sputtered Fe/Si superlattices was grown to study the magnetic coupling between ferromagnetic Fe layers (30[Angstrom] thick) for Si spacer-layer thicknesses (t[sub Si]) between 10 and 40[Angstrom]. The material is ferromagnetically coupled for t[sub Si]<13[Angstrom] and antiferromagneticly coupled for 13[Angstrom]<t[sub Si]<17[Angstrom]. For t[sub Si]>17[Angstrom] the magnetic Fe layers are uncoupled. X-ray analysis indicates that the system is well layered, but that the crystal structure remains coherent only for t[sub Si]<17[Angstrom]. These results, along with our Moessbauer investigation, strongly suggest that the Si layer is crystalline for t[sub Si]<17[Angstrom], and is iron silicide in nature. For thicker spacers, Si becomes amorphous. We propose a model of the layering that is consistent with the known properties of Fe-silicide.