Physical property changes include the possible loss of magnetic properties on ferromagnetic materials.

Right in the center is a dense mass of ferromagnetic material.

Even with ferromagnetic materials, some get atoms get out of line.

These are called "ferromagnetic" materials because iron metal is the "typical" example.

But in a ferromagnetic material, all the atomic moments are aligned even without an external field.

Computing the magnetic field and force exerted by ferromagnetic materials is difficult for two reasons.

Therefore a bulk piece of ferromagnetic material in its lowest energy state has little or no external magnetic field.

A ferromagnetic material will have a dimensional change when an external magnetic field is applied.

In general, however, a ferromagnetic material concentrates and strengthens the magnetic field.

Paramagnetic and ferromagnetic materials have permeability greater than that of free space.