inverse_kittel¶
- Stoner.analysis.fitting.models.magnetism.inverse_kittel(f, g, M_s, H_k)[source]¶
Rewritten Kittel equation for finding ferromagnetic resonsance in field with frequency.
- Parameters
f (array) – Resonance Frequency in Hz
g (float) – g factor for the gyromagnetic radius
M_s (float) – Magnetisation of sample in A/m
H_k (float) – Anisotropy field term (including demagnetising factors) in A/m
- Returns
Reesonance peak frequencies in Hz
Notes
In practice one often measures FMR by sweepign field for constant frequency and then locates the peak in H by fitting a suitable Lorentzian type peak. In this case, one returns a \(H_{res}\pm \Delta H_{res}\) In order to make use of this data with
Stoner.Analysis.AnalysisMixin.lmfit()
orStoner.Analysis.AnalysisMixin.curve_fit()
it makes more sense to fit the Kittel Equation written in terms of H than frequency.\(H_{res}=- H_{k} - \frac{M_{s}}{2} + \frac{1}{2 \gamma \mu_{0}} \sqrt{M_{s}^{2} \gamma^{2} \mu_{0}^{2} + 16 \pi^{2} f^{2}}\)