Externally applied spin current

[ghost]

I am trying to simulate domain wall motion from one end of a conventional nanowire to another (Ref: Sbiaa, R., and M. Al Bahri. "Constricted nanowire with stabilized magnetic domain wall." Journal of Magnetism and Magnetic Materials 411 (2016): 113-115, Fig. 1(a), 2, 3). But I fail to do so. The parameters are-
saturation magnetization = 600e03 A/m^3
magnetic anisotropy energy = 5e04 J/m^3
exchange stiffness = 1.3e-11 J/m
current density = 8.65e11 A/m^2
spin polarization of the applied current = 0.6
damping constant = 0.014
initial magnetization = m_{x} =-1
Current is flowing along positive x-direction

`Nx := 128
Ny := 32
Nz := 1
sizeX := 200e-9
sizeY := 40e-9
sizeZ := 3e-9
SetGridSize(Nx, Ny, Nz)
SetCellSize(sizeX/Nx, sizeY/Ny, sizeZ/Nz)

edgesmooth = 8 // Smoothing edge regions to reduce the staircase effect

save(regions)

Msat = 600e03
Ku1 = 5e04
Aex = 1.3e-11
alpha = 0.014

m = uniform(-1,0,0)
relax()
saveas(m,"xyz")

J = vector(8.65e11, 0, 0)
Pol = 0.6

autosave(m, 200e-12)
autosave(m.x(), 200e-12)
autosave(m.y(), 200e-12)
autosave(m.z(), 200e-12)
tableautosave(10e-12)

run(10e-09)`

I do not know if it is the right platform for my query, but I will be really thankful if you could help in this matter.

[JLeliaert]

You will have to initialize the magnetization with a domain wall, as it will not spontaneously nucleate at these "low" current densities. to this end, you can use m=twodomain(-1,0,0,0,1,0,1,0,0) Next, your nanowire is only 200 nm long, which will make it practically impossible to study any motion. Either you will need to make the wire longer, or make use of a moving simulation window (please have a look at the Py racetrack example on http://mumax.github.io/examples.html) Finally, I would remove the autosave(m.{x,y,z}()) because this information is contained in the autosave(m, 200e-12) statement and can be extracted in post-processing. Also, the correct syntax would have been autosave(m.comp({0,1,2}), 200e-12) Best wishes, Jonathan Leliaert

…

On Wed, Aug 29, 2018 at 6:02 AM, researchAM ***@***.***> wrote: I am trying to simulate domain wall motion from one end of a conventional nanowire to another (Ref: Sbiaa, R., and M. Al Bahri. "Constricted nanowire with stabilized magnetic domain wall." Journal of Magnetism and Magnetic Materials 411 (2016): 113-115, Fig. 1(a), 2, 3). But I fail to do so. The parameters are- saturation magnetization = 600e03 A/m^3 magnetic anisotropy energy = 5e04 J/m^3 exchange stiffness = 1.3e-11 J/m current density = 8.65e11 A/m^2 spin polarization of the applied current = 0.6 damping constant = 0.014 initial magnetization = m_{x} =-1 Current is flowing along positive x-direction `Nx := 128 Ny := 32 Nz := 1 sizeX := 200e-9 sizeY := 40e-9 sizeZ := 3e-9 SetGridSize(Nx, Ny, Nz) SetCellSize(sizeX/Nx, sizeY/Ny, sizeZ/Nz) edgesmooth = 8 // Smoothing edge regions to reduce the staircase effect save(regions) Msat = 600e03 Ku1 = 5e04 Aex = 1.3e-11 alpha = 0.014 m = uniform(-1,0,0) relax() saveas(m,"xyz") J = vector(8.65e11, 0, 0) Pol = 0.6 autosave(m, 200e-12) autosave(m.x(), 200e-12) autosave(m.y(), 200e-12) autosave(m.z(), 200e-12) tableautosave(10e-12) run(10e-09)` I do not know if it is the right platform for my query, but I will be really thankful if you could help in this matter. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#189>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AF0fi9STK-AjtUteTbnqPhWroJ799jX5ks5uVhI4gaJpZM4WQyXt> .

[Liciou]

Do you know how to set 'spinangle'?