Micromagnetic simulation of a hysteresis loop with ...

Micromagnetic simulation of a hysteresis loop with Mumax 3.9.1c (CUDA 7000) setGridSize: 64x64x50 Cylinders of variable sizes with ”EdgeSmooth = 8”

Oreci Escobar da Silva (PhD Student) https://www.researchgate.net/profile/Oreci_Da_Silva March 2018

1 Results for different values of the Dcylinder

Figure 1.1: Dcylinder = 12 nm

Figure 1.2: Dcylinder = 14 nm

1

Figure 1.3: Dcylinder = 16 nm

Figure 1.4: Dcylinder = 18 nm

2

Figure 1.5: Dcylinder = 20 nm

Figure 1.6: Dcylinder = 22 nm

3

Figure 1.7: Dcylinder = 24 nm

Figure 1.8: Dcylinder = 26 nm

4

Figure 1.9: Dcylinder = 28 nm

Figure 1.10: Dcylinder = 32 nm

5

Figure 1.11: Dcylinder = 36 nm

Figure 1.12: Dcylinder = 40 nm

6

2 Program Mumax - Parameters //Permalloy Parameters (reference): //http://www-old.mpi-halle.mpg.de/mpi/publi/pdf/3948 02.pdf SetGridsize(64, 64, 50) SetCellsize(5-9, 5-9, 1e-6/50) // Cy = 1, 2, 3, 4, 5 microns EdgeSmooth = 8 setgeom( cylinder(12e-9, inf) ) // D = 10 - 90 nm Bmax := 5000 // Maximum applied magnetic field (Oe) Nsteps := 500 // Number of steps Msat = 7.96e5 // Saturation magnetization (A/m) Aex = 1.3e-11 // Exchange stiffness (J/m) Alpha = 0.5 // Landau-Lifshitz damping constant Temp = 0 // Temperature (K) FixDt = 1e-15 // Set a fixed time step, 0 disables fixed step ang := 0 // Angle applied magnetic field (degrees) Ku1 = 500 // 1st order uniaxial anisotropy constant (J/m3) anisU = vector(0, 0, 1) // Uniaxial anisotropy direction NoDemagSpins = 0 // Disable magnetostatic interaction per-spin (set to 1 to disable) m = uniform(0, 0, 1) // Reduced magnetization (unit length) tableadd(B ext) 7

for i := -Nsteps; i