Samarium Cobalt (SmCo) is a high power magnet of slightly less power than a Neodymium. The advantage with this material is its high temperature ability. These can operate at up to 250˚C. Samariums have a slight gold tinge, and do not require coating for protection.
They are more costly than other magnets, but are essential when a high temperature strong magnet is required. Other sizes are available on request.