SmCo Magnet Free Sample Samarium cobalt magnets (also known as SmCo magnets), are extremely powerful permanent magnets. Part of the rare-earth magnet family, SmCo magnets rank similarly in strength to neodymium magnets but have much higher temperature stability and higher coercivity. They can operate at temperatures up to 525掳F (300掳C). In addition, they have a very high resistance to demagnetization and to corrosion. SmCo magnets are available in numerous shapes, sizes and grades that span a website: