The growth temperature and measurement temperature dependences of soft magnetic properties and effective damping parameter of (FeCo)-Al alloy thin films

摘要

The soft magnetic properties and effective damping parameters of Fesub73/subCosub25/subAlsub2/sub alloy thin films are discussed. The effective damping parameter αsubeff/sub measured by ferromagnetic resonance for the 10 nm-thick sample is nearly constant (≈0.004 ± 0.0008) for a growth temperature Tsubs/sub from ambient to 200 °C, and then tends to decrease for higher temperatures and αsubeff/sub is 0.002 ± 0.0004 at Tsubs/sub = 300 °C. For the 80 nm-thick sample, the αsubeff/sub seems to increase with Tsubs/sub from αsubeff/sub = 0.001 ± 0.0002 at Tsubs/sub = ambient to αsubeff/sub = 0.002 ± 0.0004. The αsubeff/sub is found nearly constant (αsubeff/sub = 0.004 ± 0.0008) over a temperature range from 10 to 300 K for the 10 nm films with the different Tsubs/sub (ambient, 100 and 200 °C). Together with an increasing non-linearity of the frequency dependence of the linewidth at low Tsubs/sub, extrinsic contributions such as two-magnon scattering dominate the observed temperature dependence of effective damping and linewidth.