Magnetostriction and angular dependence of FMR linewidth in Tb-doped Ni0.8Fe0.2 thin films
Stephen E. Russek, Pavel Kabos, Robert D. McMichael, C G. Lee, William E. Bailey, R Ewasko, Steven C. Sanders
We present the dependence of the magnetostriction in Ni0.8Fe0.2 films on Tb and Gd doping concentration with the measured doping dependence of the high-frequency damping. While the magnetostriction and the high-frequency damping are correlated, the dependence is complicated. In particular, the high-frequency damping parameter α increases rapidly (α - 0.008-0.84) as the doping concentration si increased to 10%, whereas the increase in magnetostriction is similar to that observed in the Tb-doped films. Further, it is possible to achieve low magnetostriction (λ^s^-2×106 near the region of critical damping. Measurements of th angular dependence of he ferromagnetic resonance linewidth in Tb-doped Ni0.8Fe0.2 films, although the linewidths are considerably larger. This is in contract to the systems such Ni0.8Fe0.2 on NiO, which have a large angular dependence indicating that the relaxation process proceeds through he generation of spin wave. The enhanced damping in the Tb-doped films appears, therefore, to be mediated through direct phonon generation.