Magnetism
Magnetism is a class of physical phenomena that are mediated by magnetic fields. Electric currents and the magnetic moments of elementary particles give rise to a magnetic field, which acts on other currents and magnetic moments. The most familiar effects occur in ferromagnetic materials, which are strongly attracted by magnetic fields and can be magnetized to become permanent magnets, producing magnetic fields themselves. Only a few substances are ferromagnetic; the most common ones are iron, nickel and cobalt and their alloys. The prefix "" refers to iron, because permanent magnetism was first observed in lodestone, a form of natural iron ore called magnetite, FeO.
Ferrite (magnet)
A ferrite is a ceramic material made by mixing and firing large proportions iron(III) oxide (FeO, rust) blended with small proportions of one or more additional metallic elements, such as barium, manganese, nickel, and zinc. They are both electrically "non"-conductive, meaning that they are insulators, and ferrimagnetic, meaning they can easily be magnetized or attracted to a magnet. Ferrites can be divided into two families based on their resistance to being demagnetized (magnetic coercivity).