Hard ferrite (ceramic) magnets, There are mainly two types of ferrite magnets, barium ferrite (BaO.6Fe2O3) and Strontium ferrite (SrO. 6Fe2O3), Even though they exhibit low energy (compared with other permanent magnet materials) and are relatively brittle and hard, ferrite magnets have won wide acceptance due to their good resistance to demagnetization, excellent corrosion resistance and low price per Ton. In fact, measured by weight, ferrite represents more than 75 percent of the world magnet consumption. It is the first choice for most types of DC motors, magnetic separators, magnetic resonance imaging and automotive sensors.    
                                                               
Sintered ferrite magnets are avalible in isotropic magnet and anisotropic magnets, the magnetic properties are low, Since they have nearly the same magnetic properties in all directions, so, isotropic ferrite magnets can be magnetized in many different directions or in multi-poles, Anisotropic ferrite magnets have better magnetic properties compare with isotropic ferrite magnet. However, this type of magnets can only be magnetized along a preferred direction.