ABSTRACT
Commonly, ferromagnetic or ferrimagnetic materials are considered as magnetic materials although other materials (diamagnetic and paramagnetic) also exhibit some magnetic properties, as discussed earlier. The magnetic materials can be further classi£ed into two clearly separate categories: soft magnetic materials and hard magnetic materials. Coercivity is assumed as the main criterion, and IEC Standard 404-1 recommends the coercivity of 1000 A/m as a value to distinguish both groups. This border is rather symbolic because both classes are completely different. From soft magnetic materials, we require the coercivity to be as small as possible (usually much less than 100 A/m) while hard magnetic materials should have coercivity as high as possible (commonly above 100,000 A/m). There is also a subclass of hard magnetic materials called semi-hard magnetic materials (with coercivity between 1,000 and 100,000 A/m). Figure 3.1 presents magnetic materials taking into account their coercivity available Vacuumschemlze who is one of the main manufacturers.
