Origins of the damping in perpendicular media: Three component ferromagnetic resonance linewidth in Co-Cr-Pt alloy films

The 9.41 GHz ferromagnetic resonance field and linewidth have been measured as a function of the angle (theta(H)) between the external magnetic field and film normal for a series of 17.5 nm thick Co-Cr-Pt alloy films. The linewidths ranged from hundreds of Oersted to kiloersted, with different values at theta(H)=0 and theta(H)=90 degrees and additional minima and maxima for theta(H)-values from 16 degrees to 64 degrees. The profiles can be fitted with a combination of inhomogeneity line broadening, grain boundary two magnon scattering, and magnon-electron (m-e) scattering processes, with a notably small Gilbert damping alpha-value of 0.004 for the m-e term. (c) 2008 American Institute of Physics.