Thickness-Dependent Structural and Magnetic Study of Co/Si/Co Trilayers Grown by Ion Beam Sputtering

Abstract

The magnetic properties of the metal/semiconductor structure can be modulated by the semiconductor layer thickness and therefore in the present paper, a series of trilayers of ion beam sputtered Cobalt–Silicon–Cobalt (Co/Si/Co) were grown to study the interface characteristics and their connections with magnetic properties. The thickness of Co layer, [Formula: see text], is fixed to 3[Formula: see text]nm, while varying the thickness of Si sandwich layer, [Formula: see text], from 1.5[Formula: see text]nm to 4[Formula: see text]nm, respectively. Grazing incidence X-ray diffraction (GIXRD), grazing incidence X-ray reflectivity (GIXRR), Atomic Force Microscopy (AFM) and Magneto-Optic Kerr Effect (MOKE) techniques were employed to study the crystal structure, surface and interface structure, morphology and magnetic characteristics of thin films. X-ray reflectivity measurements show substantial intermixing between the layers leading to trilayers of complicated structure at the interface during deposition. At [Formula: see text][Formula: see text]nm, whole Si layer is converted into silicide, whereas at higher spacer layer thickness ([Formula: see text]), in addition to silicide layer, an unreacted elemental layer of Si also remains in the spacer. A magneto-optical measurement reveals the presence of anti-ferromagnetic coupling in these samples and the strength of coupling between Co layers is found to be depended on [Formula: see text].