Samarium Cobalt (SmCo) magnets offer designers a tremendous combination of extremely high Magnetic properties, outstanding thermal stability and excellent corrosion resistance. As part of the rare earth group of permanent magnets, Samarium Cobalt (SmCo) magnets typically fall into two families of materials. They include rare earth SmCo5 and Sm2Co17, and are commonly referred to as 1:5 and 2: 17 materials.