
Ferrites, electrical steels and alloys (alsifers, permalloys) belong to the class of highly magnetic substances - they are soft magnets. A characteristic property of both soft and hard magnetic materials is magnetic hysteresis, which is widely used in many areas of human activity. In practical use, popular ferrimagnetic soft materials can be divided into groups according to the chemical composition, magnetic properties and applications of magnetic materials. Naturally, in each such group one can single out both universal materials, which are called general purpose behind the cordon, and narrowly focused, materials designed to solve individual special, sometimes very dubious tasks.