STT MTJ SWITCHING

[asif md]

 Respected sir 

Dr. Jonathan Leliaert Dr. Jeroen Mulkers

Dr. Josh Lauzier

Sir, I am encountering an issue with the code provided below. 

When the size or thickness of the free layer is 5 nm, switching is seen at 0.009 amp, but when I take the thickness to 40 nm and increase the current value to 5 amp, the switching is not observed.
Please tell how thickness affects the switching mechanism as provided in the literature. Switching current density is directly proportional to the thickness of the free layer.
Additionally, please elaborate on the effect of anisotropy energy.

// geometry
sizeX := 160e-9
sizeY := 80e-9
sizeZ := 40e-9

Nx := 64
Ny := 32
Nz := 40
setgridsize(Nx, Ny, Nz)
setcellsize(sizeX/Nx, sizeY/Ny, sizeZ/Nz)
setGeom(ellipse(sizeX, sizeY))

// set up free layer
Msat  = 1627.02e3
Aex   = 1.5e-12
alpha = 0.00682
m     = uniform(1, 0, 0)
Ku1 = 0.6e5

anisu = vector( 0, 0, 1)

// 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 := .7   // 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, 2500e-12)
tableautosave(10e-12)
tableadd(E_Total)
tableAdd(E_anis)
tableAdd(E_demag)
tableAdd(E_Zeeman)
run(5e-9)

thanks