SmCo is a rare earth magnet made from an alloy of Samarium and Cobalt to form SmCo5 or Sm2Co17 compounds. Reed Switch applications that require stronger magnets and excellent thermal stability up to temperatures of 300C can use SmCo magnets.
A samarium–cobalt (SmCo) magnet, a type of rare earth magnet, is a strong permanent magnet made of two basic elements samarium and cobalt. Actually, samarium is substituted by a portion of other rare earth elements including praseodymium, cerium and gadolinium, and cobalt is substituted by a portion of other transition metals including iron, copper and zirconium. They are available in two "series", namely SmCo5 magnets and Sm2Co17 magnets. They were developed in the early 1960s based on work done by Karl Strnat and Alden Ray at Wright-Patterson Air Force Base and the University of Dayton, respectively. In particular, Strnat and Ray developed the first formulation of SmCo5. They are generally ranked similarly in strength to neodymium magnets, but have higher temperature ratings and higher coercivity. They are brittle, and prone to cracking and chipping. Samarium–cobalt magnets have maximum energy products (BHmax) that range from 14 megagauss-oersteds (MG·Oe) to 33 MG·Oe, that is approx. 112 kJ/m3 to 264 kJ/m3; their theoretical limit is 34 MG·Oe, about 272 kJ/m3.
Sintered Samarium Cobalt magnets exhibit magnetic anisotropy, meaning they can only be magnetized in the axis of their magnetic orientation. This is done by aligning the crystal structure of the material during the manufacturing process.