Abstract
Abstract
Characteristic parameters of energy storage and loss in soft magnetic materials (SMMs), product S of initial susceptibility
χ
i
and resonance frequency
ω
r
and product L of maximum
χ
m
′
′
and half width
Δ
ω
of imaginary part, were introduced in permalloy films. Expressions of characteristic parameters were derived from Landau–Lifshits–Gilbert equation with a general anisotropic free energy model. It was found S = L equals to intrinsic quantity of SMMs
Q
≡
γ
M
s
1
+
H
⊥
/
H
∥
, where γ is the gyromagnetic ratio,
M
s
is the saturation magnetization, and
H
⊥
and
H
∥
are mutually orthogonal effective magnetic fields. In the presence of eddy current, it was found S remains equal to Q while L < Q results from inhomogeneity of microwave magnetic field caused by eddy current. Moreover, a linear scale of
L
/
S
versus Gilbert damping factor α was found in permalloy films with different thicknesses. Hence, our findings provide a new perspective on energy storage and loss of SMMs.
Funder
Higher Education Discipline Innovation Project
National Natural Science Foundation of China
Key Technologies Research and Development Program
Subject
General Physics and Astronomy