Anisotropic Magnetoresistance Effect
As consequence of the Anisotropic Magnetoresistance Effect we compute the Resistance of a layer of Permalloy by using the effect that the resistance changes with the direction of the magnetic field.
To have success with this script you have to download the following Image by right-click and save in the same folder like your script
The shape with cathodes (red, green) and Permalloy (black)
from magnum import * mesh = RectangularMesh((200, 100, 1), (4e-9, 4e-9, 10e-9)) #Building the mesh from the image isc = ImageShapeCreator("amr_shape.png", mesh) world = World( mesh, Body("left" , Material.Au(), isc.pick("red")), Body("square", Material.Py(), isc.pick("black")), Body("right" , Material.Au(), isc.pick("green")) ) solver = create_solver(world, [StrayField, ExchangeField, CurrentPath], log=True) solver.state.U_contact = 2 # volts solver.state.M = vortex.magnetizationFunction(400e-9, 200e-9, 1) writeOMF("M_initial.omf", solver.state.M) writeVTK("M_initial.vtk", solver.state.M) # I. Print resistance (resulting from Ohmic and AMR resistance). print "Total resistance:", solver.state.R_contact, "Ohm" # II. Calculate spatially resolved current density. # This needs either U_contact or I_contact specified. writeOMF("vortex-j.omf", solver.state.j) writeVTK("vortex-j.vtk", solver.state.j)
As consequence of the vortex we have a inhomogeneous current density. The total resistance is 28.83 Ohm
The z-Component of magnetization in the permalloy
The inhomogeneous current density in the permalloy