Effect of the Ni81Fe19 thickness on the magnetic properties of Ni81Fe19/Fe50Co50 bilayers

• Published in: Journal of magnetism and magnetic materials 2013-04, Vol.331, p.67-71
• Main Authors: Kotapati, S., Javed, A., Reeves-McLaren, N., Gibbs, M.R.J., Morley, N.A.
• Format: Article
• Language: English
• Subjects: Coercive force; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Interfacial magnetic properties (multilayers, magnetic quantum wells, superlattices, magnetic heterostructures); Kerr effects; Lasers; Magnetic properties; Magnetic properties and materials; Magnetic properties of surface, thin films and multilayers; Magnetic thin film; Magnetic underlayer; Magnetism; Magnetostriction; Microstructure; Physics; Saturation
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2012.11.022

The effect of the Ni81Fe19 layer thickness on the magnetic and microstructural properties of Ni81Fe19/Fe50Co50 bilayers has been studied. The thickness of the Fe50Co50 layer was held constant at 15nm, while the Ni81Fe19 layer thickness increased from 15nm to 90nm. This meant that the Fe50Co50 layer plus the top of the Ni81Fe19 layer were measured using a magneto-optic Kerr effect magnetometer as the laser skin depth is of the order of 20nm. It was found that as the Ni81Fe19 layer increased in thickness the coercive and saturation fields of the bilayer structure decreased, while the effective saturation magnetostriction constant increased, towards the Fe50Co50 bulk effective saturation magnetostriction value. ► Magnetostriction of 15nm FeCo on Si is dominated by a strong interface effect ► Using a NiFe underlayer, the interface effect between the FeCo and Si is removed. ► FeCo magnetostriction constant tends towards the bulk value as the NiFe thickness increases.