def test_zeeman_energy():
mu0 = 4 * np.pi * 1e-7
# A system of 8 cells ( not using nm units)
mesh = CuboidMesh(dx=2, dy=2, dz=2,
nx=2, ny=2, nz=2
)
sim = Sim(mesh)
Ms = 1e5
sim.set_Ms(Ms)
sim.set_m((0, 0, 1))
H = 0.1 / mu0
zeeman = Zeeman((0, 0, H))
sim.add(zeeman)
field = zeeman.compute_field()
zf = sim.get_interaction('Zeeman')
# -> ->
# Expected energy: Int ( -mu0 M * H ) dV
# Since we have 8 cells with the same M, we just sum their contrib
exp_energy = 8 * (-mu0 * H * Ms * mesh.dx * mesh.dy * mesh.dz)
assert np.abs(zf.compute_energy() - exp_energy) < 1e-10
def test_zeeman():
mesh = CuboidMesh(nx=5, ny=2, nz=1)
sim = Sim(mesh)
sim.set_m((1, 0, 0))
zeeman = Zeeman(varying_field)
sim.add(zeeman)
field = zeeman.compute_field()
assert field[6] == 1.2 * (2 + 0.5)
assert field[7] == 2.3 * 0.5
def test_zeeman():
mesh = CuboidMesh(nx=5, ny=2, nz=1)
sim = Sim(mesh)
sim.set_m((1, 0, 0))
zeeman = Zeeman(varying_field)
sim.add(zeeman)
field = zeeman.compute_field()
assert field[6] == 1.2 * (2 + 0.5)
assert field[7] == 2.3 * 0.5
