Variation of magnetization and the Landé g factor with thickness in Ni–Fe films (original) (raw)

We have measured the Landé g factor, the effective magnetization M eff , the uniaxial anisotropy H k , and the Gilbert damping parameter ␣, as a function of Permalloy film thickness from 2.5 to 50 nm. We used a pulsed inductive microwave magnetometer capable of generating dc bias fields of 35.2 kA/m ͑440 Oe͒. A significant decrease in g is observed with decreasing thickness below 10 nm. Also, M eff decreases with decreasing thickness consistent with a surface anisotropy constant of 0.196Ϯ0.025 mJ/m 2 . The decrease in g can arise from the orbital motion of the electrons at the interface not being quenched by the crystal field. We also compare our data to a model of an effective g factor suggesting that the decrease in g factor might also stem from the Ni-Fe interface with a Ta underlayer.