The structure and properties of sputter-deposited Co-Si alloy thin films

• Published in: Journal of physics. Condensed matter 2000-05, Vol.12 (17), p.4075-4089
• Main Authors: Fallon, J M, Faunce, C A, Grundy, P J
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Magnetic properties and materials; Magnetic properties of monolayers and thin films; Magnetic properties of surface, thin films and multilayers; Metals. Metallurgy; Physics; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/12/17/313

The structural and magnetic properties of Co sub 1-x Si sub x alloy thin films in the composition range 0 < x < 0.9 are investigated. The sputter-deposited thin films show a single phase hcp structure up to X approx = 0.25. For Si compositions beyond this, but with x < 0.6, electron diffraction implies a single amorphous phase with features in the diffraction patterns typical of a dense random packing of hard spheres (DHRPS). These alloys are ferromagnetic. For 0.6 < x < 0.8 additional diffraction maxima are observed that suggest the formation of at least two amorphous phases. Magnetic measurements suggest the presence of thermally unstable magnetic particles. For x > 0.7-0.8, Co atoms are incorporated in the covalent random network structure of Si and paramagnetism is observed. A correlation of the PEELS Co L sub 2 /L sub 3 edge loss intensity ratio with the effective Co moment suggests that the magnetic changes could arise from differing local environments as Si is added, rather than a change in the particle size. Compositional mapping shows that some of the films have a composition that is not spatially uniform.