püsimagnet

Püsimagnet, also known as a permanent magnet, is an object made from a material that is magnetized and creates its own persistent magnetic field. This magnetic field is always present and does not require an external source of magnetic flux. The magnetic properties of a permanent magnet arise from the alignment of its microscopic magnetic domains, which are regions within the material where the magnetic moments of atoms are aligned.

Materials used for permanent magnets are typically ferromagnetic, such as iron, nickel, cobalt, and their alloys, or rare-earth elements like neodymium and samarium. The strength and stability of the magnetic field depend on the specific material composition, its manufacturing process, and its shape. Permanent magnets are classified by their coercivity, which is a measure of their resistance to demagnetization. High-coercivity magnets, often referred to as hard magnets, retain their magnetism even when exposed to strong external magnetic fields, while low-coercivity magnets, or soft magnets, are easily magnetized and demagnetized.

The applications of permanent magnets are widespread. They are found in everyday items like refrigerator magnets, loudspeakers, electric motors, generators, compasses, and magnetic data storage devices. In industry, they are used in magnetic separators, sensors, and in medical equipment such as MRI machines. The fundamental principle behind a permanent magnet's ability to attract or repel other magnetic materials, or to induce currents in conductors, lies in its static magnetic field.