def excite_system(mesh): # Specify the stt dynamics in the simulation sim = Sim(mesh, name='dyn', driver='llg_stt') sim.set_tols(rtol=1e-12, atol=1e-14) sim.alpha = 0.05 sim.gamma = 2.211e5 sim.Ms = 8.6e5 # sim.set_m(init_m) sim.set_m(np.load('m0.npy')) # Energies A = 1.3e-11 exch = UniformExchange(A=A) sim.add(exch) anis = UniaxialAnisotropy(5e4) sim.add(anis) # dmi = DMI(D=8e-4) # sim.add(dmi) # Set the current in the x direction, in A / m # beta is the parameter in the STT torque sim.jx = -1e12 sim.beta = 1 # The simulation will run for 5 ns and save # 500 snapshots of the system in the process ts = np.linspace(0, 5e-9, 501) for t in ts: print 'time', t sim.run_until(t) sim.save_vtk() sim.save_m()