Ferrite, also known as Ceramic, magnets were formulated in the 1950s by Phillips in Holland. The major raw material used to manufacture Ferrite magnets is very inexpensive - iron oxide, more commonly known as "rust"! Due to their low cost, they are the most commonly used permanent magnets even today.
A special form of fully dense sintered ferrite magnets is produced using a flexible binder for the ferrite powder. These materials are commonly referred to as "Flexible Magnets".