(Fe2O3) Ferrite, or known as magnet.

A refrigerator magnet is typically made of a material known as ferrite, which is a type of ceramic often used for its magnetic properties. The ferrite material is combined with other materials such as plastic or rubber to create the final refrigerator magnet product.

The term "refrigerator magnet" is ambiguous and may refer to any number of types of magnets. However, typically a refrigerator magnet is going to be relatively weak and made of the most inexpensive materials available. Hard refrigerator magnets are likely iron. Flexible refrigerator magnets are made of bonded ferrite powders; barium ferrite is among the most common.

In general classification, a refrigerator magnet is a permanent magnet.

1. Neodymium magnet
2. Ferrite magnet
3. Alnico magnet
4. Samarium cobalt magnet
5. Ceramic magnet

A good magnet should do the trick. Neodymium-Ferrite-Boron magnets are a good candidate.