def relax_system(mesh):
sim = Sim(mesh, name='relax')
# sim.set_options(rtol=1e-10,atol=1e-14)
sim.alpha = 1.0
sim.gamma = 1.0
sim.mu_s = 1.0
sim.set_m(init_m)
# sim.set_m(random_m)
# sim.set_m(np.load('m_10000.npy'))
J = 1.0
exch = UniformExchange(J)
sim.add(exch)
D = 0.09
dmi = DMI(D)
sim.add(dmi)
zeeman = Zeeman([0, 0, 3.75e-3])
sim.add(zeeman)
sim.relax(dt=2.0, stopping_dmdt=1e-6, max_steps=1000,
save_m_steps=100, save_vtk_steps=50)
np.save('m0.npy', sim.spin)
def relax_system():
mesh = CuboidMesh(nx=121, ny=121, dx=0.5, dy=0.5, unit_length=1e-9)
sim = Sim(mesh, name='relax_skx')
sim.set_options(gamma=const.gamma, k_B=const.k_B)
sim.driver.alpha = 1.0
sim.mu_s = mu_s
sim.set_m(init_m)
# sim.set_m(random_m)
J = 50.0 * const.k_B
exch = UniformExchange(J)
sim.add(exch)
D = 0.09 * J
dmi = DMI(D)
sim.add(dmi)
K = 5e-3 * J
anis = Anisotropy(K, direction=(0, 0, 1), name='Ku')
sim.add(anis)
sim.add(Demag())
ONE_DEGREE_PER_NS = 17453292.52
sim.relax(dt=1e-12,
stopping_dmdt=0.1 * ONE_DEGREE_PER_NS,
max_steps=5000,
save_m_steps=100,
save_vtk_steps=100)
def excite_system(mesh):
sim = Sim(mesh, name='dyn')
# sim.set_options(rtol=1e-10,atol=1e-14)
sim.alpha = 0.04
sim.gamma = 1.0
sim.mu_s = 1.0
sim.set_m(np.load('m0.npy'))
J = 1.0
exch = UniformExchange(J)
sim.add(exch)
D = 0.09
dmi = DMI(D)
sim.add(dmi)
zeeman = Zeeman([0, 0, 3.75e-3], name='H')
sim.add(zeeman)
w0 = 0.02
def time_fun(t):
return np.exp(-w0 * t)
hx = TimeZeeman([0, 0, 1e-5], sinc_fun, name='h')
sim.add(hx, save_field=True)
ts = np.linspace(0, 20000, 5001)
for t in ts:
sim.run_until(t)
print 'sim t=%g' % t
def relax_system():
mesh = CuboidMesh(nx=121, ny=121, dx=0.5, dy=0.5, unit_length=1e-9)
sim = Sim(mesh, name="relax_skx")
sim.set_options(gamma=const.gamma, k_B=const.k_B)
sim.alpha = 1.0
sim.mu_s = mu_s
sim.set_m(init_m)
# sim.set_m(random_m)
J = 50.0 * const.k_B
exch = UniformExchange(J)
sim.add(exch)
D = 0.09 * J
dmi = DMI(D)
sim.add(dmi)
K = 5e-3 * J
anis = Anisotropy(K, direction=(0, 0, 1), name="Ku")
sim.add(anis)
sim.add(Demag())
ONE_DEGREE_PER_NS = 17453292.52
sim.relax(dt=1e-12, stopping_dmdt=0.1 * ONE_DEGREE_PER_NS, max_steps=5000, save_m_steps=100, save_vtk_steps=100)
def relax_system(mesh):
sim = Sim(mesh, name='relax')
# sim.set_options(rtol=1e-10,atol=1e-14)
sim.alpha = 1.0
sim.gamma = 1.0
sim.mu_s = 1.0
sim.set_m(init_m)
# sim.set_m(random_m)
# sim.set_m(np.load('m_10000.npy'))
J = 1.0
exch = UniformExchange(J)
sim.add(exch)
D = 0.09
dmi = DMI(D)
sim.add(dmi)
zeeman = Zeeman([0, 0, 3.75e-3])
sim.add(zeeman)
sim.relax(dt=2.0,
stopping_dmdt=1e-6,
max_steps=1000,
save_m_steps=100,
save_vtk_steps=50)
np.save('m0.npy', sim.spin)