Permanent Magnet - GI-DA


Permanent Magnet

What is a permanent magnet and what are the differences compared to an electromagnet

The magnet definition is that of a body that generates a magnetic field. It is defined as permanent magnet a body that was magnetized, and then creates its own independent magnetic field.

The permanent magnets are widely used in the field of separation, lifting and automation, and there are many examples among our products.

All the substances react in some way to the presence of a magnetic field, but there are materials that react in a more intense manner: these are the so called ferromagnetic materials. Some examples are iron, nickel, cobalt, some alloys of rare earths and some natural minerals such as magnetite. These are materials which are strongly attracted to a magnet and that can be magnetized themselves to create a permanent magnet.

A permanent magnet is therefore made by ferromagnetic material, magnetized thanks to a very intense external magnetic field, and maintains the magnetization even when it is no longer subjected to the external magnetic field.

What happens in a permanent magnet?
To understand it one must descend to the level of the particles that make up the substances. Each of these particles has a magnetic field, established by the so-called spin. Normally, however, the spins "link" in different directions and then, at the macroscopic level, cancel each other out. In the permanent magnets, instead, there is a sorting "long-range" of the spins, because the particles interact with each other. The higher the "sorting" that is created between the spins of the particles, the greater the magnetic field generated by the permanent magnet.

One way to get an even stronger magnetic field is directing all the spins of a ferromagnetic material using a less intense field. This is accomplished by wrapping around the magnet a conductive material in which an electric current is forced to pass. So you pass from a permanent magnet to an electromagnet.

Normally then an electromagnet generates a stronger magnetic field than that generated by a permanent magnet; there are, however, permanent magnets generated with neodymium or high "Hc" ferrite that can generate magnetic fields of intensity comparable to that produced by electromagnets.

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