1. Little or no use of materials

Magnet stone, a variety of Fe ₃ O ₄ magnetite, is a natural magnet known since ancient times. Since the end of the 19th century, several categories of metallic materials for permanent magnets have been used. Some have been completely abandoned, others may still be used in very small proportions. But all are part of the history of permanent magnets. Let's take a quick look at these permanent magnet materials (tables 1 and 2 ).

For basic information on materials with hard magnetic properties, please refer to