The ability of a magnet to attract various metal objects to itself is probably well known to everyone. Not to mention the use of magnets in medicine and other industries. How does the magnet work and what substances does it attract besides iron?
What is a magnet and how is it arranged?
A magnet is a body that has its own magnetic field. Magnets come in several forms:
- Permanent - products that after a single magnetization retain this property. Magnets are divided into several subspecies depending on the strength and other parameters.
- Temporary - operate on the principle of constants, but only when they are located in a strong magnetic field. For example, products from the so-called soft iron (nails, paper clips, etc.).
- Solenoids are wires tightly wound around the frame. Typically, such a device is equipped with an iron core. It only works if an electric current passes through the wire.
A permanent magnet is the most common and common. For its manufacture, the following combinations of materials are most often used:
- neodymium-iron-boron;
- Alniko or UNDK alloy (iron, aluminum, nickel, cobalt);
- cobalt samarium;
- ferrites (compounds of iron oxides and other ferrimagnet metals).
Any magnet has a south and north pole. The same poles repel, and the opposite ones attract.
Interesting fact: magnets are often made in the shape of a horseshoe. This is done so that the poles are located as close to each other as possible. Thus, a strong magnetic field is created, which is able to attract larger parts of the metal.
Why does a magnet attract only certain substances?
The principle of its operation is based on the creation of a magnetic field using moving electrons. In general, an electron is the simplest magnet. And any charged particle in motion forms a magnetic field. If there are many moving particles, and their movement occurs around one axis, a body with magnetic properties is obtained.
Why, then, does a magnet not attract all substances in a row? The composition of the atom includes the nucleus, as well as electrons orbiting around it. Electrons have special levels on which they rotate, or orbits. At each such level, 2 electrons are located. Moreover, they rotate in different directions.
However there are substances called ferromagnets. Some electrons are unpaired. Accordingly, a certain number of them can rotate in the same direction. This creates a magnetic field around each atom of matter.
Usually atoms are in random order. In this case, the fields balance each other. But if you direct the magnetic fields of all atoms in one direction, you get a magnet. It is noteworthy that different metals and other substances can be attracted, but much weaker than ferromagnets.To feel the attraction, you need to use a very strong magnet.
Ferromagnets include metals such as iron, cobalt, nickel, gadolinium, terbium, dysprosium, holmium, erbium. Also, some metal alloys and compounds are characterized by similar properties. The number of ferromagnets of nonmetallic origin is not so large or has not been studied much. These include, for example, chromium oxide.
Magnetic susceptibility is characterized by substances (mainly metals) that have a certain structure. They are called ferromagnets - these are substances in which the magnetic fields of atoms add up in one direction. In addition to iron, cobalt, nickel, terbium, gadolinium, dysprosium, holmium, erbium belong to ferromagnets. Also, a magnet attracts certain alloys and even non-metallic substances - for example, chromium oxide.
