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Publication Citation: Variation of the effective magnetization and the Lande g factor with thickness in thin Permalloy films

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Author(s): John P. Nibarger; Radek Lopusnik; Thomas J. Silva; Zbigniew J. Celinski;
Title: Variation of the effective magnetization and the Lande g factor with thickness in thin Permalloy films
Published: July 07, 2003
Abstract: We have simultaneously measured the Lande g factor, the effective magnetization, Meff, and the uniaxial anisotropy, Hk, and the Gilbert damping parameter α, 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 Oe). A significant decrease in g is observed with decreasing thickness below 10 nm. Also, Meff decreases with decreasing thickness consistent with a surface anisotropy constant of 0.196{plus or minus}mJ/m2. The decrease in g can arise from the orbital motion of the electrons at the interface not being quenched by the crystal filed. 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.
Citation: Applied Physics Letters
Volume: 83
Issue: 1
Pages: pp. 93 - 95
Keywords: g-factor;kittel equation;magnetometer;pulsed inductive microwave;surface anisotropy;
Research Areas: Electromagnetics
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