Permanent magnets are materials where the magnetic field is generated by the internal structure of the material itself.

• Neodymium iron boron (NdFeB) – Permanent magnet

sintered neodymium magnet, bonded (Compression Molding and Injection Molding)

• Samarium cobalt (SmCo) – Permanent magnet

SIntered SmCo magnet and bonded magnet

• Alnico – Permanent magnet

sintered or cast alnico

• Ceramic or ferrite magnets – Permanent magnet

The strongest permanent magnets in the world are neodymium (Nd) magnets, they are made from magnetic material made from an alloy of neodymium, iron and boron to form the Nd2Fe14B structure.

A permanent magnet is one that retains its magnetic properties for a long period of time. … Temporary magnets are those that simply act like permanent magnets when they are within a strong magnetic field. Unlike permanent magnets however, they loose their magnetism when the field disappears.

What is the difference between permanent magnet and electromagnet?
A permanent magnet is an object made of a material that gets magnetized and creates its own persistent magnetic field. An electromagnet is made from a coil of wire that acts as a magnet when an electric current is allowed to pass through it

There is a strange thing that a manufacturer usually test the magnetic material data like BHmax, Br and Hcj or Hcb. When the users usually look at the force or Torque, surface mgnetic flux etc. there are something different on the data between the manufacturers and the users. If you are a users, when you choose a magnetic material need to convert the material data to your requirement. when you ask a supplier for your new design, need to supply more information about envirnment like working temperature. As an example, we have client design TPS sensors for automotive, the customer will ask us to supply samples according to their working temperatue, and magnetic surface magnetic flux etc. we supply sintered alnico magnet and bonded neodymium magnet samples for their request, finally with their testing and finally choose sintered alnico magnet.