There are several different dynamics terms that are implemented in micromagneticmodel
. Here, we will provide a short list of them, together with some basic properties.
The main parameter required for the precession term is the gyrotropic ratio gamma
. Optionally, name
can be given to the dynamics term.
import micromagneticmodel as mm
precession = mm.Precession(gamma0=2.211e5)
The values of its arguments are
precession.gamma0
221100.0
precession.name
'precession'
String and LaTeX representations are
repr(precession)
'Precession(gamma0=221100.0)'
precession
Damping dynamics term requires Gilbert damping $\alpha$ to be provided. Optionally, name
can be given as well.
damping = mm.Damping(alpha=0.1)
The values of attributes are
damping.alpha
0.1
damping.name
'damping'
String and LaTeX representations are
repr(damping)
'Damping(alpha=0.1)'
damping
This dynamics term requires the non-adiabatic factor $\beta$ and velocity vector $\mathbf{u}$ to be passed. As before, name
is optional as well.
zhangli = mm.ZhangLi(u=1e6, beta=0.5)
The attributes are:
zhangli.u
1000000.0
zhangli.beta
0.5
String and LaTeX representations are
repr(zhangli)
'ZhangLi(u=1000000.0, beta=0.5)'
zhangli
For time-dependent current terms please refer to this notebook.
Dynamics equation of the micromagnetic system is the sum of dynamics terms. For instance, if we sum two dynamics terms, we get:
type(precession + damping)
micromagneticmodel.dynamics.dynamics.Dynamics
If we assign this value to a separate variable, we can explore some of its properties.
dynamics = precession + damping
The string representation is:
repr(dynamics)
'Precession(gamma0=221100.0) + Damping(alpha=0.1)'
Similarly, the LaTeX representation is
dynamics
This dynamics equation consists of two dynamics term. To add another term to it +=
operator can be used.
dynamics += zhangli
Dynamics equation is now
dynamics
There are two ways of retrieving an individual dynamics term from the dynamics equation. Let us say we want to change the value of the Gilbert damping constant $\alpha$.
If a dynamics term with name mydynamicsterm
was added to the Hamiltonian, that term can be accessed by typing hamiltonian.nydynamicsterm
.
dynamics.damping
dynamics.damping.alpha
0.1
dynamics.damping.alpha = 5e-3
dynamics.damping.alpha
0.005
Similarly, the precession term is
dynamics.precession