Dynamic anisotropy of thin Permalloy films measured by use of angle-resolved pulsed inductive microwave magnetometry

Abstract

In this study, angle-resolved pulsed inductive microwave magnetometry is used to investigate the symmetry of the dynamic anisotropy of thin Permalloy films. We measured the dynamic anisotropy field as a function of angle between the easy axis and the applied bias field. We found that, in addition to the expected uniaxial anisotropy, there is a rotatable component of anisotropy. This component of the anisotropy is present only during the dynamics measurements and is attributed to surface effects in the thin films. However, the native oxide layer is not the cause of the rotatable anisotropy components in these films.

Precise determination of the spectroscopic g-factor by use of broadband ferromagnetic resonance spectroscopy

“…A rotatable anisotropy has been observed in Permalloy thin films. 61 In fact, the magnitude of the rotatable anisotropy was found to be a function of the Permalloy thickness, 62 which is consistent with the thickness variation seen in Fig. 4, as well as the presence of the asymptotic behavior in the out-of-plane geometry.…”

Exchange coupling driven omnidirectional rotatable anisotropy in ferrite doped CoFe thin film

“…Further experiments as shown in Fig. 4 (a) is to study the angular dependence of the high frequency permeability spectra1617.The results shown in Fig. 4 (b) indicates that the high frequency response of these films are isotropic.…”

High frequency characteristics of NiO/(FeCo/NiO)10 multilayers with exchange anisotropy

“…This deviation gradually reduces with increasing Fe 65 Co 35 layer thickness; e.g., when t FM reaches 15 nm, the discrepancy between dynamic and static effective fields decreases to 75 Oe. One reasonable hypothesis is that dynamic in-plane anisotropy of the ferromagnetic films exchange coupled to NiO can be decomposed into three components [19], i.e., uniaxial anisotropy, unidirectional exchange bias and, additionally, angle independent rotatable anisotropy, which depends linearly on inverse film thickness and affects complex permeability of films when measured in the gigahertz range [20].…”