The ferromagnetic materials may be divided into the two groups:
Soft magnetic materials
The materials which have a steeply rising magnetisation curve, relatively small and narrow hysteresis loop and small energy loss per cycle of magnetisation are called soft magnetic material. These are generally used for cores of transformer, alternator etc. These are soft iron, silicon steel, nickel iron alloy and soft ferrites.
Hard magnetic materials
The materials which have gradually rising magnetisation curve, large hysteresis loop area and consequently large energy losses for each cycle of magnetisation are called hard magnetic materials. Such materials are used for making permanent magnets. These are carbon steel, tungsten steel, cobalt steel, Alnico, hard ferrities etc.