/*****************************************************************  

  Description: 
   This mumax3 scripts simulates the switch of a spin-torque MRAM 
   stack consisting of a fixed layer, spacer and free layer, using
   the Slonczewski model.

   This file is written for the mumax3 workshop organised for the 
   spintronic seminar series in the summer of 2020. For more 
   information go to https://www.mumax.ugent.be/mumax3-workshop
  
  Authors:

   Dr. Jonathan Leliaert (jonathan.leliaert@ugent.be)
   Dr. Jeroen Mulkers    (jeroen.mulkers@ugent.be)

******************************************************************/

// geometry
sizeX := 160e-9
sizeY := 80e-9
sizeZ := 5e-9

Nx := 64
Ny := 32
 
setgridsize(Nx, Ny, 1)
setcellsize(sizeX/Nx, sizeY/Ny, sizeZ)
setGeom(ellipse(sizeX, sizeY))

// set up free layer
Msat  = 800e3
Aex   = 13e-12
alpha = 0.01
m     = uniform(1, 0, 0)

// set up fixed layer polarization
angle := 20
px := cos(angle * pi/180)
py := sin(angle * pi/180)
fixedlayer = vector(-px, -py, 0)

// set up fixed and spacer layer parameters
lambda       = 1
Pol          = 0.5669
epsilonprime = 0

// send current
Jtot := 0.008            // total current in A
area := sizeX*sizeY*pi/4
jc   := Jtot / area       // current density in A/m2
J = vector(0, 0, jc)

// schedule output & run
autosave(m, 100e-12)
tableautosave(10e-12)
run(1e-9)