Ferromagnetic resonance properties of granular Co-Cr-Pt films measured by micro-fabricated coplanar waveguides

Ferromagnetic resonance (FMR) spectroscopy of granular Co-Cr-Pt films has been studied by means of a vector network analyzer. Though the granular Co-Cr-Pt films have weak magnetic susceptibility, the structural optimization of a coplanar waveguide (CPW) enables the measurement of the weak FMR signal of granular Co-Cr-Pt films, which are a promising medium for magnetic recording. The observed FMR spectra are consistent with the Kittel formula. The optimization of the CPW is well established by our simple model, providing a method to explore the basic magnetic properties of a granular medium.