Distribution of switching fields in thin films with uniaxial magnetic anisotropy

• Published in: Journal of magnetism and magnetic materials Vol. 329; pp. 170 - 177
• Main Authors: Yakovlev, N.L., Tay, Y.Y., Tay, Z.J., Chen, H.V.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2013; Elsevier
• Subjects: Anisotropy; Cobalt thin film; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Exponential functions; Grooves; Magnetic properties and materials; Magnetic properties of monolayers and thin films; Magnetic properties of surface, thin films and multilayers; Nanomaterials; Nanostructure; Physics; Self assembly; Switching; Switching field distribution; Thin films; Two-axis VSM; Uniaxial magnetic anisotropy; Switching field distribution; Uniaxial magnetic anisotropy; Two-axis VSM; Cobalt thin film; Magnetization reversal; Magnetization; Surface morphology; Magnetic hysteresis; Cobalt; Switching; Magnetic thin films; Field distribution; Stoner model; Magnetic anisotropy
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2012.09.062

Cobalt films with in-plane anisotropy were studied using two-axis magnetometry. Uniaxial anisotropy was induced in Co films by linear features on the substrate. These linear features were formed by various means: self-assembly of CaF2 grooves, nano-imprinting, and high energy atom flux or steps on vicinal surface of Si. From the analysis of components of magnetisation parallel and perpendicular to the applied field, it was found that the extrinsic switching field distribution (SFD) of all samples was an exponential function of the field. Modelling of hysteresis loops with this SFD gives good fit with experiments for linear features studied. It follows that the exponential SFD is a common property of magnetic thin films having in-plane uniaxial anisotropy and magnetisation reversal as coherent rotation. ► Two axis VSM analysis was used to analyse films with in-plane uniaxial anisotropy. ► Dip in total magnetisation at reversal is the switching field distribution. ► Switching field distribution is an exponential function of magnetic field. ► Switching field distribution is independent of the origin of anisotropy. ► Both components of magnetisation are modelled with only two adjustable parameters.