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

Published

July 7, 2003

Author(s)

John P. Nibarger, Radek Lopusnik, Thomas J. Silva, Zbigniew J. Celinski

Abstract

We have simultaneously measured the Lande g factor, the effective magnetization, M_eff, and the uniaxial anisotropy, H_k, 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, M_eff decreases with decreasing thickness consistent with a surface anisotropy constant of 0.196plus 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

Pub Type

Journals

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Keywords

g-factor, kittel equation, magnetometer, pulsed inductive microwave, surface anisotropy

Citation

Nibarger, J. , Lopusnik, R. , Silva, T. and Celinski, Z. (2003), Variation of the effective magnetization and the Lande g factor with thickness in thin Permalloy films, Applied Physics Letters, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=31261 (Accessed October 3, 2025)