mfm

Create a magnetic force microscopy instance.

class MFM

Bases: FieldQuantity

__init__(input, grid)

Create an MFM instance.

This class is used to create a magnetic force microscopy image. The needle is simulated as a pair of monopoles with a charge of 1/µ0 at a distance tipsize from one another. Here µ0 is the vacuum permeability. The height of the needle is determined by the origin of the input grid, which gets multiplied by the cellsize of the world, and the lift of the needle.

When the eval function is called for this instance, it returns a numpy array of the same size as the input grid which contains the potential energy due to the interaction of the magnet(s) and the needle.

Parameters:

• input (can be either a mumaxplus.World or mumaxplus.Magnet instance. If it is a) – World, all magnets in that world will be used to calculate the potential energy at the tip.

• grid (this is a mumaxplus.Grid instance used as a scanning surface.) – Physically, this is the plane on which the MFM needle moves.

property name

The name of the MFM instance

property unit

The unit of the MFM instance. This is always J.

property lift

The height of tip of the needle above the z component of the origin of the input grid.

default = 10e-9 m.

property tipsize

The distance between the two monopoles in the needle.

default = 1e-3 m.