`SpinWaveToolkit.BulkPolariton`#

class SpinWaveToolkit.BulkPolariton(Bext, material, epsilon, kxi=array([1.00000000e-06, 5.02512662e+00, 1.00502522e+01, 1.50753779e+01, 2.01005035e+01, 2.51256291e+01, 3.01507547e+01, 3.51758804e+01, 4.02010060e+01, 4.52261316e+01, 5.02512572e+01, 5.52763829e+01, 6.03015085e+01, 6.53266341e+01, 7.03517597e+01, 7.53768853e+01, 8.04020110e+01, 8.54271366e+01, 9.04522622e+01, 9.54773878e+01, 1.00502513e+02, 1.05527639e+02, 1.10552765e+02, 1.15577890e+02, 1.20603016e+02, 1.25628142e+02, 1.30653267e+02, 1.35678393e+02, 1.40703518e+02, 1.45728644e+02, 1.50753770e+02, 1.55778895e+02, 1.60804021e+02, 1.65829147e+02, 1.70854272e+02, 1.75879398e+02, 1.80904523e+02, 1.85929649e+02, 1.90954775e+02, 1.95979900e+02, 2.01005026e+02, 2.06030152e+02, 2.11055277e+02, 2.16080403e+02, 2.21105528e+02, 2.26130654e+02, 2.31155780e+02, 2.36180905e+02, 2.41206031e+02, 2.46231157e+02, 2.51256282e+02, 2.56281408e+02, 2.61306533e+02, 2.66331659e+02, 2.71356785e+02, 2.76381910e+02, 2.81407036e+02, 2.86432162e+02, 2.91457287e+02, 2.96482413e+02, 3.01507538e+02, 3.06532664e+02, 3.11557790e+02, 3.16582915e+02, 3.21608041e+02, 3.26633167e+02, 3.31658292e+02, 3.36683418e+02, 3.41708543e+02, 3.46733669e+02, 3.51758795e+02, 3.56783920e+02, 3.61809046e+02, 3.66834171e+02, 3.71859297e+02, 3.76884423e+02, 3.81909548e+02, 3.86934674e+02, 3.91959800e+02, 3.96984925e+02, 4.02010051e+02, 4.07035176e+02, 4.12060302e+02, 4.17085428e+02, 4.22110553e+02, 4.27135679e+02, 4.32160805e+02, 4.37185930e+02, 4.42211056e+02, 4.47236181e+02, 4.52261307e+02, 4.57286433e+02, 4.62311558e+02, 4.67336684e+02, 4.72361810e+02, 4.77386935e+02, 4.82412061e+02, 4.87437186e+02, 4.92462312e+02, 4.97487438e+02, 5.02512563e+02, 5.07537689e+02, 5.12562815e+02, 5.17587940e+02, 5.22613066e+02, 5.27638191e+02, 5.32663317e+02, 5.37688443e+02, 5.42713568e+02, 5.47738694e+02, 5.52763820e+02, 5.57788945e+02, 5.62814071e+02, 5.67839196e+02, 5.72864322e+02, 5.77889448e+02, 5.82914573e+02, 5.87939699e+02, 5.92964825e+02, 5.97989950e+02, 6.03015076e+02, 6.08040201e+02, 6.13065327e+02, 6.18090453e+02, 6.23115578e+02, 6.28140704e+02, 6.33165830e+02, 6.38190955e+02, 6.43216081e+02, 6.48241206e+02, 6.53266332e+02, 6.58291458e+02, 6.63316583e+02, 6.68341709e+02, 6.73366834e+02, 6.78391960e+02, 6.83417086e+02, 6.88442211e+02, 6.93467337e+02, 6.98492463e+02, 7.03517588e+02, 7.08542714e+02, 7.13567839e+02, 7.18592965e+02, 7.23618091e+02, 7.28643216e+02, 7.33668342e+02, 7.38693468e+02, 7.43718593e+02, 7.48743719e+02, 7.53768844e+02, 7.58793970e+02, 7.63819096e+02, 7.68844221e+02, 7.73869347e+02, 7.78894473e+02, 7.83919598e+02, 7.88944724e+02, 7.93969849e+02, 7.98994975e+02, 8.04020101e+02, 8.09045226e+02, 8.14070352e+02, 8.19095478e+02, 8.24120603e+02, 8.29145729e+02, 8.34170854e+02, 8.39195980e+02, 8.44221106e+02, 8.49246231e+02, 8.54271357e+02, 8.59296483e+02, 8.64321608e+02, 8.69346734e+02, 8.74371859e+02, 8.79396985e+02, 8.84422111e+02, 8.89447236e+02, 8.94472362e+02, 8.99497488e+02, 9.04522613e+02, 9.09547739e+02, 9.14572864e+02, 9.19597990e+02, 9.24623116e+02, 9.29648241e+02, 9.34673367e+02, 9.39698493e+02, 9.44723618e+02, 9.49748744e+02, 9.54773869e+02, 9.59798995e+02, 9.64824121e+02, 9.69849246e+02, 9.74874372e+02, 9.79899498e+02, 9.84924623e+02, 9.89949749e+02, 9.94974874e+02, 1.00000000e+03]), iota=1.5707963267948966)#

Compute wave characteristic in dependance to k-vector (wavenumber) such as frequency, group velocity, lifetime and propagation length.

Models the magnon-polariton in a bulk ferromagnets. Due to the low wavevectors of the magnon-polariton regime, this model can be also used for the modeling the magnon-polariton in thin films.

The model is based on: Linear and nonlinear spin waves in magnetic films and superlattices edited by Michael G. Cottam (1994), chapter 1.2.4 ISBN 981-02-1006-X

Parameters:

Bextfloat

external magnetic field.

materialMaterial

Instance of Material describing the magnetic layer material. Its properties are saved as attributes, but this object is not.

epsilonfloat

() real part of the dielectric constant of the material, ideally at frequencies close to ferromagnetic resonance.

kxifloat or ndarray, optional

(rad/m) k-vector (wavenumber), usually a vector.

iotafloat or ndarray, optional

(rad) angle between external field and propagation direction.

Attributes:

[same as Parameters (except `material`), plus these]

Msfloat

saturation magnetization (A/m)

gammafloat

gyromagnetic ratio (rad*Hz/T)

alphafloat

() Gilbert damping.

mu0dH0float

inhomogeneous broadening.

w0float

(rad*Hz) parameter in Slavin-Kalinikos equation. w0 = MU0*gamma*Hext

wMfloat

(rad*Hz) parameter in Slavin-Kalinikos equation. w0 = MU0*gamma*Ms

Methods

`GetDispersion`()	Gives frequencies for defined k (dispersion relation) for both hybridized modes.
`GetGroupVelocity`()	Gives (tangential) group velocities for defined k and both hybridized modes.

See also

SingleLayer, SingleLayerNumeric, Material

Examples

Example of calculation of the dispersion relation f(k_xi), and other important quantities, for a magnon-polariton in a bulk YIG.

kxi = np.linspace(1e-6, 1e3, 101)

YIGchar = BulkPolariton(Bext=20e-3, material=SWT.YIG,
                        epsilon=3.0, kxi=kxi, iota=np.pi/2)
disp = YIGchar.GetDispersion()*1e-9/(2*np.pi)  # GHz
vg = YIGchar.GetGroupVelocity()*1e-3  # km/s
lifetime = YIGchar.GetLifetime()*1e9  # ns
decLen = YIGchar.GetDecLen()*1e6  # um

GetDispersion()#

Gives frequencies for defined k (dispersion relation) for both hybridized modes. The returned values are in rad*Hz.

Returns:

wndarray: (rad*Hz) frequencies of the two hybridized modes. Has shape (2, kxi.shape[0]), where the first is the mode index.

GetGroupVelocity()#

Gives (tangential) group velocities for defined k and both hybridized modes. The group velocity is computed as vg = dw/dk. The result is given in m/s.

Warning

Works only when kxi.shape[0] >= 2.

Returns:

vgndarray: (m/s) tangential group velocity. Has shape (2, kxi.shape[0]), where the first is the mode index.

property Bext#: external field value (T)

property Ms#: saturation magnetization (A/m)

property epsilon#: dielectric function real value ()

property gamma#: gyromagnetic ratio (rad*Hz/T)

SpinWaveToolkit.BulkPolariton#

`SpinWaveToolkit.BulkPolariton`#