What Makes a Metal Magnetic?
Magnetism in metals comes from electrons that are unevenly distributed. This distribution creates magnetic dipoles by shifting the charge within the atom back and forth. In magnetic metals, these dipoles align, creating localized magnetic areas, each with a north and south pole. When most localized areas point in the same direction, they create a magnetic field, magnetizing the material. This magnetic force increases in strength as more domains align.
Different Types of Magnetism
There are three types of magnetism in metals: ferromagnetic, diamagnetic, and paramagnetic.
Ferromagnetic materials are what we usually view as magnetic. These are strongly attracted to magnets and maintain this magnetism even when a magnet isn’t nearby. This is due to the presence of magnetic domains, as explained in the previous section.
Paramagnetic materials aren’t magnetic under normal circumstances, but they can interact with magnets. When a magnet is nearby, small electrical currents form in the paramagnetic material due to the magnet’s movement. These cause small interactions with the magnet, which disappear again when the magnet is removed.
Diamagnetic materials aren’t magnetic under normal circumstances, but they can interact with magnets. Unlike paramagnetic materials, they repel magnetic fields. These magnetic properties disappear when the magnet is removed.
Are all Metals Magnetic?
No, all metals are not magnetic. The noble metals, metals such as aluminum, copper and it’s alloys, and even some ferrous metals such as stainless steel are non-magnetic. In some of the metals that are not magnetic, the localized magnetic domains cancel each other out since they point in different directions.
Ferrites or ceramic magnets: These are like those used in refrigerator magnets and elementary-school science experiments. They contain iron oxide and other metals in a ceramic composite. A ceramic magnet known as lodestone, or magnetite, was the first magnetic material discovered and occurs naturally. Even though the ceramic magnet has been around for so long, they weren’t commercially produced until 1952. Although they’re common and keep their magnetism, they tend to have a weaker magnetic field (known as the energy product) than other types of magnets. Metal Magnetic What Makes a Metal Magnetic?
Alnico magnets: These were developed in the 1930s and are made from aluminum, nickel and cobalt. They’re stronger than ceramic magnets, but not as strong as the ones that incorporate a class of elements known as rare-earth metals. Metal Magnetic